The hardest sudokus (new thread)

Everything about Sudoku that doesn't fit in one of the other sections

Re: The hardest sudokus (new thread)

Postby denis_berthier » Fri Mar 18, 2022 12:17 pm

.
Considering the same list of 246 expanded puzzles as above, I activated the following rules: Subsets, Finned-Fish, Tridagon elimination rule.

- 94 are solved after a tridagon elimination;

- 35 have no tridagon elimination rule (as per the definition here: http://forum.enjoysudoku.com/the-tridagon-rule-t39859.html:
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2 6 7 8 13 18 29 36 37 38 39 40 41 48 51 56 60 61 63 72 80 81 102 103 106 118 121 123 126 139 146 147 177 192 217

I didn't check if the rule would appear after whip eliminations.

This doesn't imply they don't have other applications of the "trivalue oddagon contradiction pattern". I don't have yet the means of embedding "tridagon-links" in chains.
If anyone wants to play with those 35 puzzles, I'm particularly interested in tridagon-links appearing between candidates in diagonally opposed blocks or in adjacent blocks but in different rows/columns.
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Re: The hardest sudokus (new thread)

Postby mith » Fri Mar 18, 2022 3:09 pm

denis_berthier wrote:.
Hi mith,
Until recently, problems of redundancy (puzzles with the same Singles-expansion) in the hardest collection hadn't appeared. I don't know if it's because most of the puzzles don't have Singles at the start or because nobody had looked into the problem before or because in such cases only the first found puzzle was kept.

Now that this problem is taking huge proportions, you have introduced a separate database, with contains only the Singles-expansions (most of which will not be minimal puzzles, but that's irrelevant to rating them). This is an interesting step forward.

However, there seems to appear another problem. Puzzles in the collection of Singles-expansions maybe extensions of one another, as you have already noticed. This is another kind of redundancy. It remains interesting to keep all of them in the Singles-expansions collection, but, in order to avoid redundant calculations every time one tries to use it, we also need a means of marking which is a subset of which.


I agree, and I'm open to ideas for how best to do this. There are a few different potential issues:

1. If we only track the "maximal" expanded form for each puzzle, we potentially lose information on where puzzles get "harder". Taking Loki for example, we know that its singles-expansion is 29c, but then there is a 30c form (with two 11.8 minimals) and the 31c form after T&E(singles,2). The 30c version preserves the hardest step (by SE), subject to morph dependency due to the bug discussed, but the 31c does not. Likewise, we had the case of a puzzle with no "basic" trivalue oddagon deduction (what you call the tridagon elimination) which was a subset of one which did solve with a basic deduction (IIRC, the subset puzzle needs a virtual triple from the trivalue oddagon to resolve one of the potential guardians and reduce it to one remaining guardian for the "basic" deduction).
2. It's not entirely clear how "maximal" should be defined here in the first place. Maximal in terms of staying out of T&E(2) makes sense when we're talking about the small subset of puzzles that meet that criteria, but it's easy to imagine puzzles that are even larger being in T&E(2) but still being rated highly enough to be in the database. Uniqueness of a maximal form is also certainly not guaranteed.
3. The alternative is to track these in a tree structure, with each puzzle only pointing to their closest neighbor(s). This could get very complicated to track in the database, though.

This is where solution-minlex may be most useful. If a puzzle is a subset of another puzzle, their solution-minlex forms will be identical other than the extra digit(s). Storing in this form (probably in addition to the puzzle-minlex form, for those who want to avoid the knowledge that r1 is 1-9 in order!) would allow for some quick operations to determine if a puzzle is a subset of another, in lieu of explicitly storing this information.
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Re: The hardest sudokus (new thread)

Postby mith » Fri Mar 18, 2022 4:18 pm

Possibly winding down on the current neighborhood; regardless, I'm going to have to find a stopping point soon so I can tinker with the computer (long story), I'll post a larger update at that point since I will be backing up everything anyway.

Hidden Text: Show
Code: Select all
........1......234.....5.6.....7......72.8.96.2956...8.96.52...2.86.7...75.98....  ED=11.7/1.2/1.2
........1......234.....5.6.....7......72.8.96..956..78.28..7...57.98....9.6.52...  ED=11.7/1.2/1.2
........1......234.....5.......6......62.7.89.2859...7.89.52...2.7..6...65.87.9..  ED=11.7/1.2/1.2
........1......234....25.......6......6..7.89.2859...7.89.52...2.79.6...65.87....  ED=11.7/1.2/1.2
........1...234.....2..5.....6.....7.2....18.78..9.6...671..9.82.8.....691....72.  ED=11.7/1.2/1.2
........1......234....25.....265.....7...8...8.6.7..9..87.965..26...7...9.528....  ED=11.7/1.2/1.2
........1....23.....4..5.....6...47..78...1.99...7..86.197..6.4.8....7..6..1...98  ED=11.7/1.2/1.2
..............1..2....3..45..6.......78.....931..97.8..937.6...7.198.6..8...139..  ED=11.7/1.2/1.2
..............1..2....34.56..7.......18.9....34..17.9..8374.9..4.1.8....79...38..  ED=11.7/1.2/1.2
..............1..2....34.56..7.......18.9....34..17.9..8374....4.1.89...79...38..  ED=11.7/1.2/1.2
........1....23.....4..5..........6...6.784.9..7..918..49.....616.8..79.7.8....14  ED=11.7/1.2/1.2
..............1..2....3..45..36.7....6189.7...9..138...87......13...6.9.6.9.....8  ED=11.7/1.2/1.2
..............1..2....3..45..36.7....6189.7...9..138...87......13..86.9.6.9......  ED=11.7/1.2/1.2

Hidden Text: Show
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........1......234.....5.6...7..2....85.976..92.86.....627.8.9.7.9.56...8..92....  ED=11.6/1.2/1.2
........1......234.....5.6...728.....895.6...62..97.8..96..2...2.8.7....75.8.96..  ED=11.6/1.2/1.2
........1.....2.3......4.5...2.6..14.6.7.1...8...2.67..861.7...21..46..77.4.8....  ED=11.6/1.2/1.2
........1.....2.3......4.5...2.46..7.47.8.1..86.1.7....18.2.67..2..6...46..7.1...  ED=11.6/1.2/1.2
........1.....2.3......4.5...2.6...4.6.7.1...8...2.67..861.7...21..46..77.4.8.1..  ED=11.6/1.2/1.2
........1.....2.3......4.5...2.46..7.47.8.1..86.1.7....18.2.67..2..6..146..7.....  ED=11.6/1.2/1.2
........1.....2.3......4.5...2.6..14.6.7.....8.1.2.67..861.7...21..46..77.4.8....  ED=11.6/1.2/1.2
........1.....2.3......4.5...2.6..14.4.7.1....8..2.67..74.8....12..46..78.61.7...  ED=11.6/1.2/1.2
........1.....2.3......4.5...2.46..7.47.8.1..86.1.7.....47.1....18.2.67..2..6...4  ED=11.6/1.2/1.2
........1.....2.3......4.5...2.6...4.4.7.1....8..2.67..74.8.1..12..46..78.61.7...  ED=11.6/1.2/1.2
........1.....2.3......4.5...2.46..7.47.8.1..86.1.7.....47......18.2.67..2..6..14  ED=11.6/1.2/1.2
........1.....2.3......4.5...2.6.....174..86..4.8...12.267.....1.42.8..678..16...  ED=11.6/1.2/1.2
........1.....2.3......4.5...2.6.1...671.8...41..27..8.7.8.1....84.7...26...4.7..  ED=11.6/1.2/1.2
........1.....2.3......4.5...2.6.....671.8...41..27..8.7.8......84.7..126.1.4.7..  ED=11.6/1.2/1.2
........1.....2.3......4.5...2.46..7.4..8.1..86.1.7....18.2.6..6..7.1...72..6...4  ED=11.6/1.2/1.2
........1.....2.3......4.5...2.46..7.4..8.1..86.1.7....18.2.6..6..7.....72..6..14  ED=11.6/1.2/1.2
........1.....2.3......4.5...2.6.....671.8...41..27..8.84.7..122..8.1...6...4.7..  ED=11.6/1.2/1.2
........1.....2.3......4.5...2.6.1...671.8...41..27..8.84.7...22..8.1...6...4.7..  ED=11.6/1.2/1.2
........1.....2.3......4.5...2.6.....671.8...41..27..8.7.8.1....84.7..126...4.7..  ED=11.6/1.2/1.2
........1.....2.3......4.5...2.46..7.4..8.1..86.1.7.....47.1....18.2.6..72..6...4  ED=11.6/1.2/1.2
........1.....2.3......4.5...2.46..7.4..8.1..86.1.7.....47......18.2.6..72..6..14  ED=11.6/1.2/1.2
........1.....2.3......4.5...2.6.....174..8..64.8...12.2.7.....1.42.8..678..16...  ED=11.6/1.2/1.2
........1.....2.34..2.1356.........6.7..3.....89.65.......24..3...1.6.454...5.12.  ED=11.6/1.2/1.2
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Re: The hardest sudokus (new thread)

Postby denis_berthier » Fri Mar 18, 2022 4:19 pm

.
Hi mith,
Supposing that you keep the idea of 2 separate databases, they may have to contain not only different puzzle information, but also different puzzle forms.
For the database of minimals, considering the heritage, it's useful to keep their original form (which often displays the pattern they're supposed to have), with their original SER.

For the database of expanded forms, I agree that the solution-minlex form is the simplest one for all the operations one might want to do with it.
Probably, we would want a few standard scripts for extracting typical parts of the database of expanded forms:
- minimum puzzles in it (wrt to the inclusion relation),
- maximum puzzles in it (wrt to the inclusion relation),
- all the puzzles larger than one and smaller than another (wrt to the inclusion relation)...
The order in which the puzzles are printed could be obtained by applying a depth-first "search" of the inclusion tree, with decreasing SERs within each level, with maybe a leading space added at each level. (The number of clues is totally irrelevant when rating a puzzle and should not be used for ordering them.)

The relation between the two databases would be easy if each puzzle in this second database has a unique identifier: add it as a new field in the database of minimals.

As for the possibly multiple SER values for different morphs of a puzzle, I think it's a false problem, entirely due to the inconsistencies of SE. The simplest solution is to keep the SER value for the form of the puzzle present in the database (including for the 2nd database); no need to re-compute all the old puzzles of the first.
That a puzzle can have morphs with higher or lower SER is a curiosity with no intrinsic meaning; we all have known this for a long time (though your recent examples beat all the previous ones). And in any case, the SER value of a puzzle is only an indication about its complexity. (This is true for any rating.)

Now, that's only my view of it, based on what I do with it. Indeed, I don't know who else uses this database. It would be interesting to have some input from other users.
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Re: The hardest sudokus (new thread)

Postby mith » Fri Mar 18, 2022 4:32 pm

To be clear, the concern in point 1 above is not about the morph-dependency caused by the known SE bug, but rather the (morph-independent) differences between a puzzle and its subset puzzles. Differences here give an indication of the complexity of obtaining the extra digit(s). (And this isn't specific to SE - we may at some point want to determine the complexity according to SudoRules for obtaining these extra digits, for example, or any other rating system. Likewiwse for T&E classification differences, if any turn out to be in T&E(subsets,2) but not T&E(singles,2), etc.)

Anyway, all that can be handled however people find it useful, so long as we can easily link puzzles by the inclusion relation. Since I'll be writing scripts to generate all this information in the first place, it will be easy to modify those for extraction purposes.
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Re: The hardest sudokus (new thread)

Postby marek stefanik » Fri Mar 18, 2022 4:35 pm

denis_berthier wrote:35 have no tridagon elimination rule (as per the definition here: http://forum.enjoysudoku.com/the-tridagon-rule-t39859.html:
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2 6 7 8 13 18 29 36 37 38 39 40 41 48 51 56 60 61 63 72 80 81 102 103 106 118 121 123 126 139 146 147 177 192 217
Thank you for the list.
In all of them, the guardians are confined in a single band.
For each puzzle I've added its skfr after that step (or btte, if it is solvable with basics), for a few hardest puzzles I've also added a rating after relabeling in one of the TH boxes.

Most puzzles only require an AIC with one extra strong link.
Code: Select all
.-----------------------.-------------------.---------------------.
| 235689  34567  235678 | 35679  3568  3569 | 479    2489  1      |
| 5689    14567  5678   | 15679  568   2    | 479    3     48     |
| 2389    137    2378   | 1379   4     39   | 5      6     28     |
:-----------------------+-------------------+---------------------:
| 28     #356    28     | 3569  #356   7    | 13469  1459  3456   |
|#356     3567   4      | 8      1    #356+9| 2     b57–9  356    |
| 1       9     #356+7  |#356    2     4    | 8     a57    356    |
:-----------------------+-------------------+---------------------:
|#356     8      9      | 24    #356   1    | 346    245   7      |
| 4       2     #356    |#356    7     8    | 136    15    9      |
| 7      #356    1      | 24     9    #356  | 346    2458  234568 |
'-----------------------'-------------------'---------------------'
9r5c6 == 7r6c3 – 7r6c8 = 7r5c8 => –9r5c8
AIC 1+TH; 2, 8, 13, 29, 39, 41, 48, 51, 56, 103, 106, 118, 121, 126, 139, 177, 192: Show
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........1.....2.3.....4.56......7.....481.2..19..248...89..1..742..78..97.1.9....; btte
........1.....234...5.136.2....7..36....894....46......125...6.4.3...52.56....1..; 6.7
........1.......23.....45.6...45.....478.96..95..678...69.48...4..97...878...5...; 9.0 -> 6.6 b4
........1.....2.3.....4.562.....7.....481.2..19..248...89..1..742..78..97.1.9....; btte
........1.....234...5.136.2....7..36....894....46......125...6.4.31..52.56....1..; btte
........1.....234..35.14.62....7.4.6....89.3...36......125..6..3.4...25.56.....1.; 6.7
........1.....234..35.14.62....78.3....39.4.6..36......125..6..3.4...25.56.....1.; btte
........1.......23....456.7...6.4....45.897..86.75.9...7849....4..5.8..959..6....; 9.0 -> 6.6 b4
........1.....2.34..2...5.6...23.....278.9.4.93..47.8..49.28...2..97...878...3...; 8.9 -> 6.6 b4
........1.....234..35.14.62....7.4.6....89.3...36......125..6..3.41..25.56.....1.; btte
........1.....2345.23...67...8.9...7.6723.....9.8.7....8962.7..63..78...7.2..9...; 7.1
........1.....234..35.14.62....78.3....39.4.6..36......125..6..3.41..25.56.....1.; btte
........1.....2.34235...6...26..78..3.8...7.657........52.78.6.68.23....7.35.6...; 6.6
........1.....2.34.25...6.7.6.58....28..79...5.92....8.98.257..6.2......75.96.8..; 8.9 -> 6.6 b8
........1.....2.34235...6...26..78..3.8.2.7.657......2.5..78.6.68.23....7..5.6...; 6.6
........1.....2345.23...67...8.9...7.6723.....9.8.7....8962.7..63..78...7.2..98..; 7.1
........1.....2.34235...6...26..78..3.8.2.7.657........52.78.6.68.23....7.35.6...; 6.6

Some require an AHP.
Code: Select all
.------------------.-----------------.--------------------.
|b3457  3468 a3479 | 3489   347  346 | 589    1      2    |
|b257–1 1268 a279  | 289    27   26  | 3      589    4    |
| 234   2348  2349 | 23489  1    5   | 6      7      89   |
:------------------+-----------------+--------------------:
| 2347 #234   8    | 15     9   #234 | 12457  2345   6    |
|#234   5     1    |#234    6    7   | 2489   23489  389  |
| 6     9    #234+7| 15    #234  8   | 12457  2345   1357 |
:------------------+-----------------+--------------------:
|#234+1 7     5    |#234    8    9   | 124    6      13   |
| 8     1234 #234  | 6      5   #234 | 12479  2349   1379 |
| 9    #234   6    | 7     #234  1   | 2458   23458  358  |
'------------------'-----------------'--------------------'
1r7c1 == 7r6c3 – 7r12c3 = 57r12c1 => –1r2c1
AIC AHP+TH; 18, 60, 61, 63, 80, 81, 123, 146, 147: Show
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........1.....2.34..2...56...578.....276.9...98..2.....6859.7..25.......7.92.86..; 8.3
.......12......3.4....1567...8.9...6.51.67...69...8....75.89.6.8..65....9.67.1...; 8.3
.......12......3.4....1567...8.9...6.51.76...69...8....75.89.6.8..65....9.67.1...; 7.3
........1.......23...2456.....7.4..5..5.827.6.7.56.8...874...6.46...7...5.26.8...; 6.6
........1.....2.34.25...67..6.58....28..79...5.92......98.657..6.2......75.92.8..; 7.3
........1.....2.34.25...67..6.58....28..79...5.92......98.257..6.2......75.96.8..; 8.3
........1.......23...2456.....7.4.....5.827.6.7.56.8...8745..6.46..27...5.26.8...; 6.6
.......12......3.4....1567...8.9...6.51.67...69...8....75.89.6.8..65..9.9.67.1...; 8.3
.......12......3.4....1567...8.9...6.51.76...69...8....75.89.6.8..65..9.9.67.1...; 7.3

Some have three guardians and require a short kraken or whip.
Code: Select all
.-----------------------.---------------------.-------------------.
| 24      24      #789+6 | 3789   A3569 A35678 | 5789  #789   1    |
| 16789  #789     16789 | 789   bB169–5 2     | 3      4    #789+5|
|#789+1   3       5     | 789    a19    4     |#789    6     2    |
:-----------------------+---------------------+-------------------:
| 1289    2589    189   | 23      7     135   | 4      289   6    |
| 12467   2457    167   | 24      8     9     | 157    3     57   |
| 124789  245789  3     | 6       245   15    | 15789  2789  5789 |
:-----------------------+---------------------+-------------------:
|#789     1       2     | 5       349   378   | 6     #789   34   |
| 3      #789     4     | 1       69    678   | 2      5    #789  |
| 5       6      #789   | 234789  2349  378   |#789    1     34   |
'-----------------------'---------------------'-------------------'
TH 789b1379 using internals:
| 6r1c3 – 6r1c56 = 6r2c5
| 1r3c1 – 1r3c5 = 1r2c5
| 5r2c9
=> -5r2c5
Kraken 2+TH; 7, 38, 40, 72: Show
Code: Select all
........1.....234...5..36.2....7..36....894....46......125...6.4.31..52.56....1..; btte
........1.....234..35..4.62....7.4.6....89.3...36......125..6..3.41..25.56.....1.; btte
........1.....234...5..36.2....784.....49..36..46......125...6.4.31..52.56....1..; btte
........1.....234..35..4.62....78.3....39.4.6..36......125..6..3.41..25.56.....1.; btte

A few (all subgrids of the last one) have a short nice loop with two bi-value cells.
Code: Select all
.-----------------------.-------------------.----------------------.
| 3456–9 378–9   345678 | 56789 #789   5789 | 12      12     #789  |
|b69     78–9    1      |#789+6  2     3    |#789     4       5    |
|a59     78–9    2      | 1      4    #789+5| 3      #789     6    |
:-----------------------+-------------------+----------------------:
| 123–9  123789  378    | 23     6    #789  | 4       5      #789  |
| 23–9   5       378    | 23    #789   4    | 6      #789     1    |
| 4–9    6       478    |#789    5     1    |#789     3       2    |
:-----------------------+-------------------+----------------------:
| 12356  4       356    | 5789   1789  5789 | 125789  126789  3789 |
| 7      13      356    | 4589   189   2    | 1589    1689    3489 |
| 8      12      9      | 457    3     6    | 1257    127     47   |
'-----------------------'-------------------'----------------------'
6r2c4 == 5r3c6 – (5=9)r3c1 – (9=6)r2c1 – Loop => -9r1456c1, -9r123c2
NL 2+TH; 6, 36, 37, 102: Show
Code: Select all
...........1.23.45..214.3.6......45..5...46.1.6..51.32.4.......7....2...8.9.36...; 7.8
...........1.23.45..214.3.6....6.45..5...46.1.6..51.32.4.......7....2...8.9.36...; 7.8
...........1.23.45..214.3.6......45..5...46.1.6..51.32.4.......7....2...829.36...; 7.8
...........1.23.45..214.3.6....6.45..5...46.1.6..51.32.4.......7....2...829.36...; 7.8

Finally, in one we have to use an almost SDC.
Code: Select all
.----------------------.------------------.---------------------.
| 23456–9 25–789 2456–9| 56     3789 #789 |#789   4789    1     |
|*4569   *5789  *4569  |*56    #789   1   | 2     3      #4789  |
|*39     *789    1     |#789+3  2     4   | 5    #789     6     |
:----------------------+------------------+---------------------:
| 12459   259    3     | 4789   1789  789 | 6     124789  45789 |
| 149     6      49    | 34789  5     2   | 3789  14789   4789  |
| 7       259    8     | 349    139   6   | 39    1249    459   |
:----------------------+------------------+---------------------:
| 289     1      279   |#789    6     5   | 4    #789     3     |
| 689     3      679   | 2      4    #789 | 1     5      #789   |
| 589     4      579   | 1     #789   3   |#789   6       2     |
'----------------------'------------------'---------------------'
3r3c4 == 4r2c9 – (4=356789)(r2c1234, r3c12) – Loop => –789r1c123
NL ASDC+TH: Show
Code: Select all
........1.....123...1.245.6..3...6...6..52...7.8..6....1..654.3.3.24.15..4.1.3.62; btte

The last one shows how beneficial it can be to use the externals, as the same eliminations are available using the virtual triple in r1.
It can also be used in a few other puzzles, such as the four puzzles with the NL 2+TH.

Marek
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Re: The hardest sudokus (new thread)

Postby denis_berthier » Fri Mar 18, 2022 4:40 pm

mith wrote:To be clear, the concern in point 1 above is not about the morph-dependency caused by the known SE bug, but rather the (morph-independent) differences between a puzzle and its subset puzzles. Differences here give an indication of the complexity of obtaining the extra digit(s). (And this isn't specific to SE - we may at some point want to determine the complexity according to SudoRules for obtaining these extra digits, for example, or any other rating system. Likewiwse for T&E classification differences, if any turn out to be in T&E(subsets,2) but not T&E(singles,2), etc.)

That was clear.
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Re: The hardest sudokus (new thread)

Postby denis_berthier » Fri Mar 18, 2022 5:17 pm

marek stefanik wrote:
denis_berthier wrote:35 have no tridagon elimination rule (as per the definition here: http://forum.enjoysudoku.com/the-tridagon-rule-t39859.html:
Code: Select all
2 6 7 8 13 18 29 36 37 38 39 40 41 48 51 56 60 61 63 72 80 81 102 103 106 118 121 123 126 139 146 147 177 192 217
Thank you for the list.
For each puzzle I've added its skfr after that step (or btte, if it is solvable with basics), for a few hardest puzzles I've also added a rating after relabeling in one of the TH boxes.

This confirms what I had noticed with the puzzles having a tridagon elimination: after it, they become (relatively) easy.
This may be due to the pattern implying few possibilities for the erst of the grid.
At this point, I think we can't draw any general conclusion about the puzzles not in T&E(2). We would need more varied cases.


marek stefanik wrote:In all of them, the guardians are confined in a single band.

=> band or stack by row/col symmetry.
But I can't see any a priori reason why they couldn't be in diagonally opposite blocks. Waiting for more examples.
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Re: The hardest sudokus (new thread)

Postby mith » Fri Mar 18, 2022 6:03 pm

The pattern can certainly exist with guardians in opposing boxes:

Code: Select all
67..8....8.4..9....5946......5.47..89.75...6..8.6..5.......48......7..93...9...2.  ED=9.0/1.2/1.2


(This is in T&E(1), never mind T&E(2). But I don't see why harder puzzles with this pattern couldn't exist as well.)

Perhaps at some point I can code up a check for this type of pattern among the database puzzles and try doing neighborhood T&E searches.
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Re: The hardest sudokus (new thread)

Postby marek stefanik » Fri Mar 18, 2022 8:08 pm

In this one, neither guardian can be eliminated using T&E(1).
Code: Select all
32.....81......7.........45.62.83...73.61.2..8..7.2....73.61...6.83.....21.8.7...; skfr 10.1; non-minimal
.-------------------.-------------------.---------------------.
| 3     2     45679 | 459   4579  4569  | 69      8      1    |
| 1459  4589  14569 | 1459  3459  45689 | 7       2369   2369 |
|*19    8–9   167–9 |*129   237–9 68–9  | 36–9    4      5    |
:-------------------+-------------------+---------------------:
|#459+1 6     2     |#459   8     3     | 1459    1579   479  |
| 7     3    #459   | 6     1    #459   | 2       59     8    |
| 8    #459   1459  | 7    #459   2     | 134569  13569  3469 |
:-------------------+-------------------+---------------------:
|#459   7     3     |#459+2 6     1     | 8       259    249  |
| 6    #459   8     | 3     2459 #459   | 1459    12579  2479 |
| 2     1    #459   | 8    #459   7     | 34569   3569   3469 |
'-------------------'-------------------'---------------------'
(9=1)r3c1 – 1r4c1 == 2r7c4 – (2=19)r3c14 => –9r3c23567; 9.0 skfr, then relabeling in b5 or b8 reduces it to 7.8

Marek
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Re: The hardest sudokus (new thread)

Postby mith » Fri Mar 18, 2022 9:46 pm

marek stefanik wrote:Some have three guardians and require a short kraken or whip.
Code: Select all
.-----------------------.---------------------.-------------------.
| 24      24      #789+6 | 3789   A3569 A35678 | 5789  #789   1    |
| 16789  #789     16789 | 789   bB169–5 2     | 3      4    #789+5|
|#789+1   3       5     | 789    a19    4     |#789    6     2    |
:-----------------------+---------------------+-------------------:
| 1289    2589    189   | 23      7     135   | 4      289   6    |
| 12467   2457    167   | 24      8     9     | 157    3     57   |
| 124789  245789  3     | 6       245   15    | 15789  2789  5789 |
:-----------------------+---------------------+-------------------:
|#789     1       2     | 5       349   378   | 6     #789   34   |
| 3      #789     4     | 1       69    678   | 2      5    #789  |
| 5       6      #789   | 234789  2349  378   |#789    1     34   |
'-----------------------'---------------------'-------------------'
TH 789b1379 using internals:
| 6r1c3 – 6r1c56 = 6r2c5
| 1r3c1 – 1r3c5 = 1r2c5
| 5r2c9
=> -5r2c5
Kraken 2+TH; 7, 38, 40, 72: Show
Code: Select all
........1.....234...5..36.2....7..36....894....46......125...6.4.31..52.56....1..; btte
........1.....234..35..4.62....7.4.6....89.3...36......125..6..3.41..25.56.....1.; btte
........1.....234...5..36.2....784.....49..36..46......125...6.4.31..52.56....1..; btte
........1.....234..35..4.62....78.3....39.4.6..36......125..6..3.41..25.56.....1.; btte


I love these. If either 1 or 6 were a guardian in box 1, you get the virtual triple in row 2 placing the 5 as a guardian in r2c9; and of course if neither 1 nor 6 is a guardian, 5 has to be by TH. (Note only the first two still have three guardians after basics - the others place a 1 in r3c5.)
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Re: The hardest sudokus (new thread)

Postby mith » Fri Mar 18, 2022 10:38 pm

mith wrote:Ok, here are the results - I've gone from 88 expanded puzzles to 246:


Here are another 118 (for a total of 375), generated from the existing batch by digit swapping within isolated patterns (999_Springs' algorithm):

[edit]There may be a few duplicates in this list, I was missing a check at one point in my code. This is fixed, but I've generated a whole lot more from the minimals so I'm going to finish this process and then post the whole list again.[/edit]

Code: Select all
..............1.23....45.67.23....898.7...3.696.8..27..39......28.......7.6.9..32;29
..............1.23....45.67.27....8986....37.9.38..2.6.39......28.......7.6.9..32;29
.............12.34.13..45.2....6..25....789.3...5......491...5.1.5.....932.9...41;29
........1.....2.34....56....17......2.8......65..27..8.2678.1..17..65...8.52.17..;29
........1....23.....4..5..........67..6.781.9..7.6948..48...69.16.9..7.87.9....14;30
..............1.23....45.67.23....898.7...3.696.8..27..39......28.....9.7.6.9..32;30
........1....23.....4..5..........67..6.7819...7.694.8.48...9.616.9..78.7.9....14;30
..............1.23....45.67.27....8986....37.9.38..2.6.39......28.....9.7.6.9..32;30
........1....12.3....45.67.....8529....9......5912.8...48..1..95.2.98..491..4....;30
.............12.34.13..45.2....6..25...2789.3...5......491...5.1.5.....932.9...41;30
........1.....2.34.35.......56......7.3..58.682...67...8725..6.3.26.8...56..37...;30
........1.....2.34....56....17..8...2.8......65..27..8.2678.1..17..65...8.52.17..;30
........1.....2.34....56....17......2.8.....765..27..8.2678.1..17..65...8.52.17..;30
........1.....2.......3..45.16.23...27.81.6..3.87.61...32.87..61.7.6...868.......;30
........1.....2..3....45.67.1485.9..5.2.91...89.2.41...29......1.8......45..28.1.;30
........1.....2..3....45.67.158.49..2.8.91...49.25.1...54.28.1.8.1......92.......;30
........1.....2.3..45.3..26.....716......834..6.52.....24...61.13.2...545.6...2.3;30
........1....23....24....35....46....4273.6.8.6.8.27...76..4.8.2.3.78...48..6....;30
........1....23....24....35....46....4273.6.8.6.8.27...86..4...2.3.87...47..6..8.;30
........1..2..1.3..3..45.26....5261....46.2.32....3.45..7...16...8...35.42.5.....;30
........1.12.34....561.7..........68......9.5.65.9.21..98...5.652....18.6.18...92;31
........1.12.34....561.7..........68......9.5.65.9.21..98...1.65.1....8262.8..59.;31
........1....12.3....45678.....9526....6......5612.9...49..1..65.2.69..461..4....;31
........1.....2....34...256....37.....78.4.9..4392..78.794.3...3.827....42..89...;31
........1.....2..3....45.67.1485.9..5.2.91...89.2.41...29.1....1.8......45..28.1.;31
........1.....2..3....45.67.158.49..2.8.91...49.25.1...54.28.1.8.1......92..1....;31
........1.....2.3.....45..6.1457.8..5.28.17..78..241...51..8...42..57..88.7......;31
........1.....2.3.....45..6.15..7..82.4.58..787........2857.1..1.7.24...54.8.17..;31
........1.....2.3.....45..6.15..7..82.4.58..787........4857.1..1.7.24...52.8.17..;31
........1.....2.3.....45..6.15..7..84.2.58..787........4857.1..52.8.17..7.1.24...;31
........1.....2.3..45.3..26.....716......834.46.52.....24...61.13.2...545.6...2.3;31
........1.....2.34....56....17..8...2.8.....756..27..8.2587.1..18..65...7.62.18..;31
........1.....2.34....56....17..8...2.8.....756..27..8.2687.1..18..65...7.52.18..;31
........1.....2.34....56....17..8...2.8.....765..27..8.2587.1..18..65...7.62.18..;31
........1.....2.34....56....17..8...2.8.....765..27..8.2678.1..17..65...8.52.17..;31
........1.....2.34....56....17..8...2.8.....765..27..8.2687.1..18..65...7.52.18..;31
........1.....2.34.35.......56......7.3.258.682...67...8725..6.3.26.8...56..37...;31
........1....12.3....45.672....8529....9......5912.8...48..1..95.2.98..491..4....;31
........1....12.3....45678.....2596....6......561.92...19.6...45.2.94..664...1...;31
........1....12.3....45678.....6925....5......5612.9...94..1..55.1.4....62..95..4;31
........1....23.....4..5..........67..7.684.9.46.7918..78....144.9...8.661.8..79.;31
........1....23.....4..5..........67..7.6849..46.791.8.78....144.9...68.61.8..7.9;31
........1....23....24....35....46....4273...8.6.8.27...762.4.8.2.3.78...48.36....;31
........1....23....24....35....62.....273.8.6..68.47...6834....24..78.6.3.72.6...;31
........1....23.45234........2.67....6.2.8.7..7834.....26......7.3..68..84..326.7;31
........1....23.45234........2.67.8..6.2.8....7834.....26......74..326.88.3..67..;31
........1..2..1.3..3..45.26....5261....46.2.32....3.45..7...16...8...35.42.5.6...;31
........1..2..3.4..4.56..23....362.4...25.31.2..4.1.65..7...13...8...45.62.3.....;31
........1..2.13.4..4.56..23...3.52.4...62.31.2...4..56..7...13...8...46.52...6...;31
.......12......3.4..1.2356.....14.23.1.3.54.6.4.26.15.1.......57...3....8.9.56...;31
.......12......3.4..1.2356.....14.53.1.36.42..4.2.51.61.......57...3....8.9.56...;31
........1....23..4....56.78.12......3.9..1...56..32.1..23.19...1.63.59..95.26.1..;32
........1....23..4....56.78.12......3.9..1...56..32.1..53.19...12.36.9..9.62.51..;32
........1.12.34....561.7..........85..8...6.9.65.8.12..89....5652....91.6.19..8.2;32
........1.12.34....561.7..........85..8...6.9.65.8.12..89....165.1...9.262.9..85.;32
........1....12.3....456782....9526....6......5612.9...49..1..65.2.69..461..4....;32
........1....23..4....56.78.12......3.9.1....65..32.1..63.91...1.526.9..92.3.51..;32
.......12......3.4..1.2356.....14.53.1.36.42..4.2.51.61.......57.8.56...95..3....;32
........1....23..4....56.78.12......3.9.1....65..32.1..23.91...16.2.59..9.536.1..;32
.......12......3.4..1.2356.....14.23.1.3.54.6.4.26.15.1.......57.8.56...95..3....;32
........1.....2....34...256....37.....78.4.9..4392..78.794.38..3.827....42..89...;32
........1.....2.3.....45..6.1457.8..5.28.17..78..241...51..7..842..58..78.7......;32
........1.....2.3.....45..6.1457.8..5.28.17..78..241...51..8..742..57..88.7......;32
........1.....2.3.....45..6.15..7..82.4.58..787........2857.1..1.7.248..54.8.17..;32
........1.....2.3.....45..6.15..7..82.4.58..787........4857.1..1.7.248..52.8.17..;32
........1.....2.3.....45..6.15..7..84.2.58..787........4857.1..52.8.17..7.1.248..;32
........1.....2.34....56..7.16..8..92.5.69..898........5968.1..1.8.259..62.9.1...;32
........1.....234.235.......56.278..32.6.8...7.835.....732.5.6858...6.7.6.2......;32
........1....12.3....456782....2596....6......561.92...19.6...45.2.94..664...1...;32
........1....12.3....456782....6925....5......5612.9...94..1..55.1.4....62..95..4;32
........1....23....24....35....62.....67.48..4.283.7.6.6734....24..87.6.3.82.6...;32
........1....23....24....35....62....6.7.48..24.83.7.6.7634....38.2.6...4.2.78.6.;32
........1....23....24....35....62....6.7.48..24.83.7.6.7634....38.2.6...4.2.87.6.;32
........1....23....24....35....62....6.7.48..24.83.7.6.8634....37.2.6...4.2.78.6.;32
........1....23....24....35....62....6.7.48..24.83.7.6.8634....37.2.6...4.2.87.6.;32
........1....23....24...35.....46....4273..68.6.8.2.7..762.48..2.3.78...48.36....;32
........1....23....24...35.....46....4273..68.6.8.2.7..762.48..2.3.87...48.36....;32
........1....23....24...35.....46....4273..68.6.8.2.7..863.4...2.3.87...47.26.8..;32
........1....23..4....56.78.12......3.9..1...56..32.1..23.19...15.26.9..9.63.51..;32
........1....23..4....56.78.12......3.9..1...56..32.1..53.19...1.62.59..92.36.1..;32
........1....23.4..25...3.6....57....5283...437.4.2.8..872.54..2...84...54.37....;32
........1..2..3.4..4.56..23....362.4...25.31.2..4.1.65..7...13...8...45.62.3.5...;32
........1..2.13.4..4.56..23...3.52.4...62.31.2...4..56..7...13...8...46.52..36...;32
.......12.....13.4..1.2356.....14.23.1.3.54.6.4.26.15.1.......57...3....8.9.56...;32
.......12.....13.4..1.2356.....14.53.1.36.42..4.2.51.61.......57...3....8.9.56...;32
.......12.....13.4..1.3256.....14.23.1.26.45..4.3.51.61.......57...23...8.9.56...;33
.......12.....13.4..1.3256.....14.53.1.2.54.6.4.36.12.1.......57...23...8.9.56...;33
........1.....2.3..45...267....48.....83.5.9..5492..83.895.43..4.328....52..39...;33
.......12.....13.4..1.2356.....14.53.1.36.42..4.2.51.61.......57.8.56...95..3....;33
.......12.....13.4..1.2356.....14.23.1.3.54.6.4.26.15.1.......57.8.56...95..3....;33
........1.....234.235....6..57.286..32.7.6...8.635.....832.5.7656...7.8.7.2......;33
........1....23.4..25...36.....57....5283..74.7.4.2.8..872.54..2.3.84...54.37....;33
........1....23.4..25...36.....57....5283..74.7.4.2.8..872.54..2.3.48...54.37....;33
........1....23.4..25...36.....57....5283..74.7.4.2.8..473.5...2.3.48...58.27.4..;33
.......12.....13.4..1.2356.....14.23.1.3.54.6.4.26.15.1.......57...32...8.9.56...;33
.......12.....13.4..1.2356.....14.53.1.36.42..4.2.51.61.......57...32...8.9.56...;33
........1....23....24...356...2.7.....7.84.9..4239..78.79.428..2.873....43.8.9...;33
........1....23.4..25...3.6....57....5283...437.4.2.85.872.54..2...84...54.37....;33
........1....2345.234.......23.678..6.82.4...74.38.....82.7..6.3.7......46..32.78;33
........1....2345.234.......23.678..74.38....8.62.4....82.7..6.3.7......46..32.78;33
........1....2345.234.......26......7.3..6.8.84..32.67.7834....36.2.87..4.2.67...;33
........1....2345.234.......26..7.8.37.......4.8.32.76.43.76...68.24....7.23.86..;33
........1....2345.234.......26.7..8.37.......4.8.32.76.43.67...68.2.4...7.238.6..;33
.......12.....13.4..1.3256.....14.23.1.3.54.6.4.26.15.1.......57...23...8.9.56...;33
.......12.....13.4..1.3256.....14.53.1.36.42..4.2.51.61.......57...23...8.9.56...;33
.......12.....13.4..1.3256.....14.23.1.26.45..4.3.51.61.......57.8.56...95..23...;34
.......12.....13.4..1.3256.....14.53.1.2.54.6.4.36.12.1.......57.8.56...95..23...;34
.......12.....13.4..1.2356.....14.53.1.36.42..4.2.51.61.......57.8.56...95..32...;34
.......12.....13.4..1.2356.....14.23.1.3.54.6.4.26.15.1.......57.8.56...95..32...;34
........1....2345.234....6..26.7..8.37.......4.8.32.76.43.67...68.2.4...7.238.6..;34
........1....2345.234....6..26..7.8.37.......4.8.32.76.43.76...68.24....7.23.86..;34
........1....2345.234....6..23.786..7.62.4...84.36.....62.8..7.3.8......47..32.86;34
........1....2345.234....6..23.786..6.72.4...84.36.....62.8..7.3.8......47..32.86;34
........1....2345.234....6..27......6.3..7.8.84..32.76.6834....37.2.86..4.2.76...;34
........1....23.4..25...367...2.8.....8.45.9..5239..84.89.524..2.483....53.4.9...;34
.......12.....13.4..1.3256.....14.23.1.3.54.6.4.26.15.1.......57.8.56...95..23...;34
.......12.....13.4..1.3256.....14.53.1.36.42..4.2.51.61.......57.8.56...95..23...;34
........1....23.4..25...367...2.8....5239..84.8..45.9..98.524..24.83....5.39.4...;34


Going to check minimals next, I would guess most are not in the database yet. Given the way they were produced, there won't be anything novel in terms of trivalue oddagon patterns in the expanded forms, but it's always possible there will be some minimals that expand only to a subset of one of these.
mith
 
Posts: 996
Joined: 14 July 2020

Re: The hardest sudokus (new thread)

Postby denis_berthier » Sat Mar 19, 2022 5:53 am

marek stefanik wrote:
denis_berthier wrote:35 have no tridagon elimination rule (as per the definition here: http://forum.enjoysudoku.com/the-tridagon-rule-t39859.html:
Code: Select all
2 6 7 8 13 18 29 36 37 38 39 40 41 48 51 56 60 61 63 72 80 81 102 103 106 118 121 123 126 139 146 147 177 192 217
Thank you for the list.
In all of them, the guardians are confined in a single band.

I've coded "tridagons links" between pairs of candidates (no triplets and no rule using these links are coded).
It seems I find fewer than you: only 18. [Edit: ah no, wait; I hadn't tried the full list; I now find 33)
Also, the numbers of candidates and the paths suggest there remains much redundancy in the list.

#2
Code: Select all
Resolution state after Singles and whips[1]:
   +----------------------+----------------------+----------------------+
   ! 235689 34567  235678 ! 35679  3568   3569   ! 479    2489   1      !
   ! 5689   14567  5678   ! 15679  568    2      ! 479    3      48     !
   ! 2389   137    2378   ! 1379   4      39     ! 5      6      28     !
   +----------------------+----------------------+----------------------+
   ! 23568  356    23568  ! 3569   356    7      ! 13469  1459   3456   !
   ! 356    3567   4      ! 8      1      3569   ! 2      579    356    !
   ! 1      9      3567   ! 356    2      4      ! 8      57     356    !
   +----------------------+----------------------+----------------------+
   ! 356    8      9      ! 23456  356    1      ! 346    245    7      !
   ! 4      2      356    ! 356    7      8      ! 136    15     9      !
   ! 7      356    1      ! 23456  9      356    ! 346    2458   234568 !
   +----------------------+----------------------+----------------------+
196 candidates.

hidden-pairs-in-a-column: c4{n2 n4}{r7 r9} ==> r9c4≠6, r9c4≠5, r9c4≠3, r7c4≠6, r7c4≠5, r7c4≠3
hidden-pairs-in-a-row: r4{n2 n8}{c1 c3} ==> r4c3≠6, r4c3≠5, r4c3≠3, r4c1≠6, r4c1≠5, r4c1≠3
extended tridagon for digits 3, 5 and 6 in blocks:
b4, with cells: r6c3 (link cell), r5c1, r4c2
b5, with cells: r6c4, r5c6 (link cell), r4c5
b7, with cells: r8c3, r7c1, r9c2
b8, with cells: r8c4, r7c5, r9c6
==> tridagon-link(n7r6c3, n9r5c6)


#6
Code: Select all
Resolution state after Singles and whips[1]:
   +----------------------+----------------------+----------------------+
   ! 34569  3789   345678 ! 56789  6789   5789   ! 12789  12789  789    !
   ! 69     789    1      ! 6789   2      3      ! 789    4      5      !
   ! 59     789    2      ! 1      4      5789   ! 3      789    6      !
   +----------------------+----------------------+----------------------+
   ! 1239   123789 378    ! 236789 6789   789    ! 4      5      789    !
   ! 239    5      378    ! 23789  789    4      ! 6      789    1      !
   ! 49     6      478    ! 789    5      1      ! 789    3      2      !
   +----------------------+----------------------+----------------------+
   ! 12356  4      356    ! 5789   1789   5789   ! 125789 126789 3789   !
   ! 7      13     356    ! 4589   189    2      ! 1589   1689   3489   !
   ! 8      12     9      ! 457    3      6      ! 1257   127    47     !
   +----------------------+----------------------+----------------------+
196 candidates.

hidden-pairs-in-a-column: c4{n2 n3}{r4 r5} ==> r5c4≠9, r5c4≠8, r5c4≠7, r4c4≠9, r4c4≠8, r4c4≠7, r4c4≠6
hidden-single-in-a-block ==> r4c5=6
hidden-pairs-in-a-row: r1{n1 n2}{c7 c8} ==> r1c8≠9, r1c8≠8, r1c8≠7, r1c7≠9, r1c7≠8, r1c7≠7
extended tridagon for digits 7, 8 and 9 in blocks:
b2, with cells: r3c6 (link cell), r2c4 (link cell), r1c5
b3, with cells: r3c8, r2c7, r1c9
b5, with cells: r4c6, r6c4, r5c5
b6, with cells: r4c9, r6c7, r5c8
==> tridagon-link(n5r3c6, n6r2c4)


#8
Code: Select all
Resolution state after Singles and whips[1]:
   +----------------------+----------------------+----------------------+
   ! 236789 234789 6789   ! 4789   4569   45678  ! 789    5789   1      !
   ! 16789  789    16789  ! 789    569    2      ! 3      4      5789   !
   ! 789    4789   5      ! 4789   1      3      ! 6      789    2      !
   +----------------------+----------------------+----------------------+
   ! 1289   2589   189    ! 124    7      145    ! 289    3      6      !
   ! 12367  2357   167    ! 123    8      9      ! 4      157    57     !
   ! 123789 235789 4      ! 6      235    15     ! 2789   15789  5789   !
   +----------------------+----------------------+----------------------+
   ! 789    1      2      ! 5      349    478    ! 789    6      34789  !
   ! 4      789    3      ! 1789   69     1678   ! 5      2      789    !
   ! 5      6      789    ! 234789 2349   478    ! 1      789    34789  !
   +----------------------+----------------------+----------------------+
200 candidates.

hidden-pairs-in-a-column: c9{n3 n4}{r7 r9} ==> r9c9≠9, r9c9≠8, r9c9≠7, r7c9≠9, r7c9≠8, r7c9≠7
hidden-pairs-in-a-row: r1{n2 n3}{c1 c2} ==> r1c2≠9, r1c2≠8, r1c2≠7, r1c2≠4, r1c1≠9, r1c1≠8, r1c1≠7, r1c1≠6
hidden-single-in-a-block ==> r3c2=4
extended tridagon for digits 7, 8 and 9 in blocks:
b3, with cells: r2c9 (link cell), r1c7, r3c8
b1, with cells: r2c2, r1c3 (link cell), r3c1
b9, with cells: r8c9, r7c7, r9c8
b7, with cells: r8c2, r7c1, r9c3
==> tridagon-link(n5r2c9, n6r1c3)


#13
Code: Select all
Resolution state after Singles and whips[1]:
   +----------------------+----------------------+----------------------+
   ! 23568  2379   234568 ! 23567  2389   236    ! 479    4789   1      !
   ! 1568   179    14568  ! 1567   189    16     ! 479    2      3      !
   ! 1238   12379  1238   ! 1237   12389  4      ! 5      789    6      !
   +----------------------+----------------------+----------------------+
   ! 12368  123    12368  ! 4      5      123    ! 12379  1379   279    !
   ! 123    4      7      ! 8      123    9      ! 6      135    25     !
   ! 9      5      123    ! 123    6      7      ! 8      134    24     !
   +----------------------+----------------------+----------------------+
   ! 1235   6      9      ! 123    4      8      ! 1237   1357   257    !
   ! 4      123    1235   ! 9      7      1236   ! 123    1356   8      !
   ! 7      8      123    ! 1236   123    5      ! 12349  13469  249    !
   +----------------------+----------------------+----------------------+
192 candidates.

hidden-pairs-in-a-row: r4{n6 n8}{c1 c3} ==> r4c3≠3, r4c3≠2, r4c3≠1, r4c1≠3, r4c1≠2, r4c1≠1
extended tridagon for digits 1, 2 and 3 in blocks:
b7, with cells: r7c1 (link cell), r8c2, r9c3
b8, with cells: r7c4, r8c6 (link cell), r9c5
b4, with cells: r5c1, r4c2, r6c3
b5, with cells: r5c5, r4c6, r6c4
==> tridagon-link(n5r7c1, n6r8c6)


#18
Code: Select all
Resolution state after Singles and whips[1]:
   +-------------------+-------------------+-------------------+
   ! 34568 3479  346   ! 3489  34567 34567 ! 289   2789  1     !
   ! 1568  179   16    ! 189   1567  2     ! 89    3     4     !
   ! 1348  13479 2     ! 13489 1347  1347  ! 5     6     789   !
   +-------------------+-------------------+-------------------+
   ! 1346  134   5     ! 7     8     134   ! 12349 1249  2369  !
   ! 134   2     7     ! 6     1345  9     ! 1348  1458  358   !
   ! 9     8     1346  ! 134   2     1345  ! 134   1457  3567  !
   +-------------------+-------------------+-------------------+
   ! 134   6     8     ! 5     9     134   ! 7     124   23    !
   ! 2     5     134   ! 134   13467 13467 ! 13489 1489  389   !
   ! 7     134   9     ! 2     134   8     ! 6     145   35    !
   +-------------------+-------------------+-------------------+
189 candidates.

hidden-pairs-in-a-row: r8{n6 n7}{c5 c6} ==> r8c6≠4, r8c6≠3, r8c6≠1, r8c5≠4, r8c5≠3, r8c5≠1
extended tridagon for digits 1, 3 and 4 in blocks:
b5, with cells: r5c5 (link cell), r6c4, r4c6
b4, with cells: r5c1, r6c3 (link cell), r4c2
b8, with cells: r9c5, r8c4, r7c6
b7, with cells: r9c2, r8c3, r7c1
==> tridagon-link(n5r5c5, n6r6c3)


#29
Code: Select all
Resolution state after Singles and whips[1]:
   +-------------------+-------------------+-------------------+
   ! 23569 34567 23567 ! 35679 3568  3569  ! 479   489   1     !
   ! 569   14567 567   ! 15679 568   2     ! 479   3     48    !
   ! 389   137   378   ! 1379  4     39    ! 5     6     2     !
   +-------------------+-------------------+-------------------+
   ! 23568 356   23568 ! 3569  356   7     ! 13469 1459  3456  !
   ! 356   3567  4     ! 8     1     3569  ! 2     579   356   !
   ! 1     9     3567  ! 356   2     4     ! 8     57    356   !
   +-------------------+-------------------+-------------------+
   ! 356   8     9     ! 23456 356   1     ! 346   245   7     !
   ! 4     2     356   ! 356   7     8     ! 136   15    9     !
   ! 7     356   1     ! 23456 9     356   ! 346   2458  34568 !
   +-------------------+-------------------+-------------------+
186 candidates.

hidden-pairs-in-a-column: c4{n2 n4}{r7 r9} ==> r9c4≠6, r9c4≠5, r9c4≠3, r7c4≠6, r7c4≠5, r7c4≠3
hidden-pairs-in-a-row: r4{n2 n8}{c1 c3} ==> r4c3≠6, r4c3≠5, r4c3≠3, r4c1≠6, r4c1≠5, r4c1≠3
extended tridagon for digits 3, 5 and 6 in blocks:
b4, with cells: r6c3 (link cell), r5c1, r4c2
b5, with cells: r6c4, r5c6 (link cell), r4c5
b7, with cells: r8c3, r7c1, r9c2
b8, with cells: r8c4, r7c5, r9c6
==> tridagon-link(n7r6c3, n9r5c6)


#36
Code: Select all
Resolution state after Singles and whips[1]:
   +----------------------+----------------------+----------------------+
   ! 34569  3789   345678 ! 56789  789    5789   ! 12789  12789  789    !
   ! 69     789    1      ! 6789   2      3      ! 789    4      5      !
   ! 59     789    2      ! 1      4      5789   ! 3      789    6      !
   +----------------------+----------------------+----------------------+
   ! 1239   123789 378    ! 23789  6      789    ! 4      5      789    !
   ! 239    5      378    ! 23789  789    4      ! 6      789    1      !
   ! 49     6      478    ! 789    5      1      ! 789    3      2      !
   +----------------------+----------------------+----------------------+
   ! 12356  4      356    ! 5789   1789   5789   ! 125789 126789 3789   !
   ! 7      13     356    ! 4589   189    2      ! 1589   1689   3489   !
   ! 8      12     9      ! 457    3      6      ! 1257   127    47     !
   +----------------------+----------------------+----------------------+
190 candidates.

hidden-pairs-in-a-column: c4{n2 n3}{r4 r5} ==> r5c4≠9, r5c4≠8, r5c4≠7, r4c4≠9, r4c4≠8, r4c4≠7
hidden-pairs-in-a-row: r1{n1 n2}{c7 c8} ==> r1c8≠9, r1c8≠8, r1c8≠7, r1c7≠9, r1c7≠8, r1c7≠7
extended tridagon for digits 7, 8 and 9 in blocks:
b2, with cells: r3c6 (link cell), r2c4 (link cell), r1c5
b3, with cells: r3c8, r2c7, r1c9
b5, with cells: r4c6, r6c4, r5c5
b6, with cells: r4c9, r6c7, r5c8
==> tridagon-link(n5r3c6, n6r2c4)


#37
Code: Select all
Resolution state after Singles and whips[1]:
   +----------------------+----------------------+----------------------+
   ! 34569  3789   345678 ! 56789  6789   5789   ! 12789  12789  789    !
   ! 69     789    1      ! 6789   2      3      ! 789    4      5      !
   ! 59     789    2      ! 1      4      5789   ! 3      789    6      !
   +----------------------+----------------------+----------------------+
   ! 1239   13789  378    ! 236789 6789   789    ! 4      5      789    !
   ! 239    5      378    ! 23789  789    4      ! 6      789    1      !
   ! 49     6      478    ! 789    5      1      ! 789    3      2      !
   +----------------------+----------------------+----------------------+
   ! 1356   4      356    ! 5789   1789   5789   ! 25789  26789  3789   !
   ! 7      13     356    ! 4589   189    2      ! 589    689    3489   !
   ! 8      2      9      ! 457    3      6      ! 157    17     47     !
   +----------------------+----------------------+----------------------+
186 candidates.

hidden-pairs-in-a-column: c4{n2 n3}{r4 r5} ==> r5c4≠9, r5c4≠8, r5c4≠7, r4c4≠9, r4c4≠8, r4c4≠7, r4c4≠6
hidden-single-in-a-block ==> r4c5=6
hidden-pairs-in-a-row: r1{n1 n2}{c7 c8} ==> r1c8≠9, r1c8≠8, r1c8≠7, r1c7≠9, r1c7≠8, r1c7≠7
extended tridagon for digits 7, 8 and 9 in blocks:
b2, with cells: r3c6 (link cell), r2c4 (link cell), r1c5
b3, with cells: r3c8, r2c7, r1c9
b5, with cells: r4c6, r6c4, r5c5
b6, with cells: r4c9, r6c7, r5c8
==> tridagon-link(n5r3c6, n6r2c4)


#39
Code: Select all
Resolution state after Singles and whips[1]:
   +----------------------+----------------------+----------------------+
   ! 236789 234789 6789   ! 4789   4569   45678  ! 789    5789   1      !
   ! 16789  789    16789  ! 789    569    2      ! 3      4      5789   !
   ! 789    4789   5      ! 4789   1      3      ! 6      789    2      !
   +----------------------+----------------------+----------------------+
   ! 1289   2589   189    ! 24     7      145    ! 289    3      6      !
   ! 12367  2357   167    ! 23     8      9      ! 4      157    57     !
   ! 123789 235789 4      ! 6      235    15     ! 2789   15789  5789   !
   +----------------------+----------------------+----------------------+
   ! 789    1      2      ! 5      349    478    ! 789    6      34789  !
   ! 4      789    3      ! 1      69     678    ! 5      2      789    !
   ! 5      6      789    ! 234789 2349   478    ! 1      789    34789  !
   +----------------------+----------------------+----------------------+
193 candidates.

hidden-pairs-in-a-column: c9{n3 n4}{r7 r9} ==> r9c9≠9, r9c9≠8, r9c9≠7, r7c9≠9, r7c9≠8, r7c9≠7
hidden-pairs-in-a-row: r1{n2 n3}{c1 c2} ==> r1c2≠9, r1c2≠8, r1c2≠7, r1c2≠4, r1c1≠9, r1c1≠8, r1c1≠7, r1c1≠6
hidden-single-in-a-block ==> r3c2=4
extended tridagon for digits 7, 8 and 9 in blocks:
b3, with cells: r2c9 (link cell), r1c7, r3c8
b1, with cells: r2c2, r1c3 (link cell), r3c1
b9, with cells: r8c9, r7c7, r9c8
b7, with cells: r8c2, r7c1, r9c3
==> tridagon-link(n5r2c9, n6r1c3)


#40
Code: Select all
Resolution state after Singles and whips[1]:
   +----------------------+----------------------+----------------------+
   ! 236789 234789 6789   ! 789    4568   45679  ! 789    5789   1      !
   ! 16789  789    16789  ! 789    1568   2      ! 3      4      5789   !
   ! 1789   4789   5      ! 789    148    3      ! 6      789    2      !
   +----------------------+----------------------+----------------------+
   ! 12369  2359   169    ! 23     7      8      ! 4      159    59     !
   ! 1278   2578   178    ! 4      9      15     ! 278    3      6      !
   ! 123789 235789 4      ! 6      235    15     ! 2789   15789  5789   !
   +----------------------+----------------------+----------------------+
   ! 789    1      2      ! 5      348    479    ! 789    6      34789  !
   ! 4      789    3      ! 1      68     679    ! 5      2      789    !
   ! 5      6      789    ! 23789  2348   479    ! 1      789    34789  !
   +----------------------+----------------------+----------------------+
192 candidates.

naked-pairs-in-a-column: c6{r5 r6}{n1 n5} ==> r1c6≠5
whip[1]: c6n5{r6 .} ==> r6c5≠5
hidden-pairs-in-a-column: c9{n3 n4}{r7 r9} ==> r9c9≠9, r9c9≠8, r9c9≠7, r7c9≠9, r7c9≠8, r7c9≠7
hidden-pairs-in-a-column: c4{n2 n3}{r4 r9} ==> r9c4≠9, r9c4≠8, r9c4≠7
whip[1]: b8n7{r9c6 .} ==> r1c6≠7
whip[1]: b8n8{r9c5 .} ==> r1c5≠8, r2c5≠8, r3c5≠8
whip[1]: b8n9{r9c6 .} ==> r1c6≠9
hidden-pairs-in-a-row: r1{n2 n3}{c1 c2} ==> r1c2≠9, r1c2≠8, r1c2≠7, r1c2≠4, r1c1≠9, r1c1≠8, r1c1≠7, r1c1≠6
hidden-single-in-a-block ==> r3c2=4
naked-single ==> r3c5=1
extended tridagon for digits 7, 8 and 9 in blocks:
b3, with cells: r2c9 (link cell), r1c7, r3c8
b1, with cells: r2c2, r1c3 (link cell), r3c1
b9, with cells: r8c9, r7c7, r9c8
b7, with cells: r8c2, r7c1, r9c3
==> tridagon-link(n5r2c9, n6r1c3)


#41
Code: Select all
Resolution state after Singles and whips[1]:
   +----------------------+----------------------+----------------------+
   ! 246789 24789  6789   ! 3789   3569   35678  ! 5789   789    1      !
   ! 16789  789    16789  ! 789    569    2      ! 3      4      5789   !
   ! 789    3      5      ! 789    1      4      ! 789    6      2      !
   +----------------------+----------------------+----------------------+
   ! 1289   2589   189    ! 123    7      135    ! 4      289    6      !
   ! 12467  2457   167    ! 124    8      9      ! 157    3      57     !
   ! 124789 245789 3      ! 6      245    15     ! 15789  2789   5789   !
   +----------------------+----------------------+----------------------+
   ! 789    1      2      ! 5      349    378    ! 6      789    34789  !
   ! 3      789    4      ! 1789   69     1678   ! 2      5      789    !
   ! 5      6      789    ! 234789 2349   378    ! 789    1      34789  !
   +----------------------+----------------------+----------------------+
194 candidates.

hidden-pairs-in-a-column: c9{n3 n4}{r7 r9} ==> r9c9≠9, r9c9≠8, r9c9≠7, r7c9≠9, r7c9≠8, r7c9≠7
hidden-pairs-in-a-row: r1{n2 n4}{c1 c2} ==> r1c2≠9, r1c2≠8, r1c2≠7, r1c1≠9, r1c1≠8, r1c1≠7, r1c1≠6
extended tridagon for digits 7, 8 and 9 in blocks:
b3, with cells: r2c9 (link cell), r1c8, r3c7
b1, with cells: r2c2, r1c3 (link cell), r3c1
b9, with cells: r8c9, r7c8, r9c7
b7, with cells: r8c2, r7c1, r9c3
==> tridagon-link(n5r2c9, n6r1c3)


#48
Code: Select all
Resolution state after Singles and whips[1]:
   +----------------------+----------------------+----------------------+
   ! 246789 24789  6789   ! 789    3568   35679  ! 5789   789    1      !
   ! 16789  789    16789  ! 789    568    2      ! 3      4      5789   !
   ! 789    3      5      ! 789    1      4      ! 789    6      2      !
   +----------------------+----------------------+----------------------+
   ! 12469  2459   169    ! 124    7      8      ! 159    3      59     !
   ! 1278   2578   178    ! 3      9      15     ! 4      278    6      !
   ! 124789 245789 3      ! 6      245    15     ! 15789  2789   5789   !
   +----------------------+----------------------+----------------------+
   ! 789    1      2      ! 5      348    379    ! 6      789    34789  !
   ! 3      789    4      ! 1789   68     1679   ! 2      5      789    !
   ! 5      6      789    ! 24789  2348   379    ! 789    1      34789  !
   +----------------------+----------------------+----------------------+
188 candidates.

naked-pairs-in-a-column: c6{r5 r6}{n1 n5} ==> r8c6≠1, r1c6≠5
hidden-single-in-a-block ==> r8c4=1
whip[1]: c6n5{r6 .} ==> r6c5≠5
hidden-pairs-in-a-column: c9{n3 n4}{r7 r9} ==> r9c9≠9, r9c9≠8, r9c9≠7, r7c9≠9, r7c9≠8, r7c9≠7
hidden-pairs-in-a-column: c4{n2 n4}{r4 r9} ==> r9c4≠9, r9c4≠8, r9c4≠7
whip[1]: b8n7{r9c6 .} ==> r1c6≠7
whip[1]: b8n8{r9c5 .} ==> r1c5≠8, r2c5≠8
whip[1]: b8n9{r9c6 .} ==> r1c6≠9
hidden-pairs-in-a-row: r1{n2 n4}{c1 c2} ==> r1c2≠9, r1c2≠8, r1c2≠7, r1c1≠9, r1c1≠8, r1c1≠7, r1c1≠6
extended tridagon for digits 7, 8 and 9 in blocks:
b3, with cells: r2c9 (link cell), r1c8, r3c7
b1, with cells: r2c2, r1c3 (link cell), r3c1
b9, with cells: r8c9, r7c8, r9c7
b7, with cells: r8c2, r7c1, r9c3
==> tridagon-link(n5r2c9, n6r1c3)


#51
Code: Select all
Resolution state after Singles and whips[1]:
   +----------------------+----------------------+----------------------+
   ! 23679  2358   234679 ! 2389   237    2367   ! 458    4589   1      !
   ! 1679   158    14679  ! 189    17     167    ! 458    2      3      !
   ! 1239   1238   1239   ! 12389  4      5      ! 6      89     7      !
   +----------------------+----------------------+----------------------+
   ! 12379  123    12379  ! 6      123    4      ! 12358  1358   258    !
   ! 123    4      5      ! 123    8      9      ! 7      136    26     !
   ! 8      6      123    ! 7      5      123    ! 9      134    24     !
   +----------------------+----------------------+----------------------+
   ! 1236   7      8      ! 4      9      123    ! 1235   1356   256    !
   ! 4      123    1236   ! 5      1237   8      ! 123    1367   9      !
   ! 5      9      123    ! 123    6      1237   ! 12348  13478  248    !
   +----------------------+----------------------+----------------------+
184 candidates.

hidden-pairs-in-a-row: r4{n7 n9}{c1 c3} ==> r4c3≠3, r4c3≠2, r4c3≠1, r4c1≠3, r4c1≠2, r4c1≠1
extended tridagon for digits 1, 2 and 3 in blocks:
b7, with cells: r7c1 (link cell), r8c2, r9c3
b8, with cells: r7c6, r8c5 (link cell), r9c4
b4, with cells: r5c1, r4c2, r6c3
b5, with cells: r5c4, r4c5, r6c6
==> tridagon-link(n6r7c1, n7r8c5)


#56
Code: Select all
Resolution state after Singles and whips[1]:
   +-------------------+-------------------+-------------------+
   ! 34568 5679  34568 ! 34567 5689  456   ! 2789  279   1     !
   ! 1568  15679 1568  ! 1567  15689 2     ! 789   3     4     !
   ! 1348  179   2     ! 1347  189   14    ! 5     79    6     !
   +-------------------+-------------------+-------------------+
   ! 14568 156   14568 ! 2     3     156   ! 1679  15679 579   !
   ! 156   2     7     ! 8     156   9     ! 136   4     35    !
   ! 9     3     156   ! 156   4     7     ! 126   8     25    !
   +-------------------+-------------------+-------------------+
   ! 1356  4     9     ! 156   2     8     ! 1367  1567  357   !
   ! 2     156   1356  ! 9     7     1456  ! 1346  156   8     !
   ! 7     8     156   ! 1456  156   3     ! 12469 12569 259   !
   +-------------------+-------------------+-------------------+
185 candidates.

hidden-pairs-in-a-row: r4{n4 n8}{c1 c3} ==> r4c3≠6, r4c3≠5, r4c3≠1, r4c1≠6, r4c1≠5, r4c1≠1
extended tridagon for digits 1, 5 and 6 in blocks:
b7, with cells: r7c1 (link cell), r8c2, r9c3
b8, with cells: r7c4, r8c6 (link cell), r9c5
b4, with cells: r5c1, r4c2, r6c3
b5, with cells: r5c5, r4c6, r6c4
==> tridagon-link(n3r7c1, n4r8c6)


#60
Code: Select all
Resolution state after Singles and whips[1]:
   +-------------------+-------------------+-------------------+
   ! 3457  3468  3479  ! 3489  347   346   ! 589   1     2     !
   ! 1257  1268  279   ! 289   27    26    ! 3     589   4     !
   ! 234   2348  2349  ! 23489 1     5     ! 6     7     89    !
   +-------------------+-------------------+-------------------+
   ! 2347  234   8     ! 12345 9     234   ! 12457 2345  6     !
   ! 234   5     1     ! 234   6     7     ! 2489  23489 389   !
   ! 6     9     2347  ! 12345 234   8     ! 12457 2345  1357  !
   +-------------------+-------------------+-------------------+
   ! 1234  7     5     ! 234   8     9     ! 124   6     13    !
   ! 8     1234  234   ! 6     5     234   ! 12479 2349  1379  !
   ! 9     234   6     ! 7     234   1     ! 2458  23458 358   !
   +-------------------+-------------------+-------------------+
184 candidates.

hidden-pairs-in-a-column: c4{n1 n5}{r4 r6} ==> r6c4≠4, r6c4≠3, r6c4≠2, r4c4≠4, r4c4≠3, r4c4≠2
extended tridagon for digits 2, 3 and 4 in blocks:
b7, with cells: r7c1 (link cell), r8c3, r9c2
b8, with cells: r7c4, r8c6, r9c5
b4, with cells: r5c1, r6c3 (link cell), r4c2
b5, with cells: r5c4, r6c5, r4c6
==> tridagon-link(n1r7c1, n7r6c3)


#61
Code: Select all
Resolution state after Singles and whips[1]:
   +-------------------+-------------------+-------------------+
   ! 3457  3468  3479  ! 3489  346   347   ! 589   1     2     !
   ! 1257  1268  279   ! 289   26    27    ! 3     589   4     !
   ! 234   2348  2349  ! 23489 1     5     ! 6     7     89    !
   +-------------------+-------------------+-------------------+
   ! 2347  234   8     ! 12345 9     234   ! 12457 2345  6     !
   ! 234   5     1     ! 234   7     6     ! 2489  23489 389   !
   ! 6     9     2347  ! 12345 234   8     ! 12457 2345  1357  !
   +-------------------+-------------------+-------------------+
   ! 1234  7     5     ! 234   8     9     ! 124   6     13    !
   ! 8     1234  234   ! 6     5     234   ! 12479 2349  1379  !
   ! 9     234   6     ! 7     234   1     ! 2458  23458 358   !
   +-------------------+-------------------+-------------------+
184 candidates.

hidden-pairs-in-a-column: c4{n1 n5}{r4 r6} ==> r6c4≠4, r6c4≠3, r6c4≠2, r4c4≠4, r4c4≠3, r4c4≠2
extended tridagon for digits 2, 3 and 4 in blocks:
b7, with cells: r7c1 (link cell), r8c3, r9c2
b8, with cells: r7c4, r8c6, r9c5
b4, with cells: r5c1, r6c3 (link cell), r4c2
b5, with cells: r5c4, r6c5, r4c6
==> tridagon-link(n1r7c1, n7r6c3)


#63
Code: Select all
Resolution state after Singles and whips[1]:
   +----------------------+----------------------+----------------------+
   ! 26789  2459   4689   ! 389    379    369    ! 459    45789  1      !
   ! 6789   459    4689   ! 189    179    169    ! 459    2      3      !
   ! 13789  139    1389   ! 2      4      5      ! 6      789    789    !
   +----------------------+----------------------+----------------------+
   ! 123689 1239   13689  ! 7      139    4      ! 1239   139    5      !
   ! 139    1349   5      ! 139    8      2      ! 7      1349   6      !
   ! 1239   7      1349   ! 5      6      139    ! 8      1349   249    !
   +----------------------+----------------------+----------------------+
   ! 139    8      7      ! 4      12359  139    ! 12359  6      29     !
   ! 4      6      139    ! 139    12359  7      ! 12359  13589  289    !
   ! 5      139    2      ! 6      139    8      ! 1349   13479  479    !
   +----------------------+----------------------+----------------------+
188 candidates.

hidden-pairs-in-a-column: c5{n2 n5}{r7 r8} ==> r8c5≠9, r8c5≠3, r8c5≠1, r7c5≠9, r7c5≠3, r7c5≠1
hidden-pairs-in-a-row: r4{n6 n8}{c1 c3} ==> r4c3≠9, r4c3≠3, r4c3≠1, r4c1≠9, r4c1≠3, r4c1≠2, r4c1≠1
extended tridagon for digits 1, 3 and 9 in blocks:
b4, with cells: r4c2 (link cell), r6c3 (link cell), r5c1
b5, with cells: r4c5, r6c6, r5c4
b7, with cells: r9c2, r8c3, r7c1
b8, with cells: r9c5, r8c4, r7c6
==> tridagon-link(n2r4c2, n4r6c3)


#72
Code: Select all
Resolution state after Singles and whips[1]:
   +----------------------+----------------------+----------------------+
   ! 246789 24789  6789   ! 789    3568   35679  ! 5789   789    1      !
   ! 16789  789    16789  ! 789    1568   2      ! 3      4      5789   !
   ! 1789   3      5      ! 789    18     4      ! 789    6      2      !
   +----------------------+----------------------+----------------------+
   ! 12469  2459   169    ! 24     7      8      ! 159    3      59     !
   ! 1278   2578   178    ! 3      9      15     ! 4      278    6      !
   ! 124789 245789 3      ! 6      245    15     ! 15789  2789   5789   !
   +----------------------+----------------------+----------------------+
   ! 789    1      2      ! 5      348    379    ! 6      789    34789  !
   ! 3      789    4      ! 1      68     679    ! 2      5      789    !
   ! 5      6      789    ! 24789  2348   379    ! 789    1      34789  !
   +----------------------+----------------------+----------------------+
186 candidates.

naked-pairs-in-a-column: c6{r5 r6}{n1 n5} ==> r1c6≠5
whip[1]: c6n5{r6 .} ==> r6c5≠5
hidden-pairs-in-a-column: c9{n3 n4}{r7 r9} ==> r9c9≠9, r9c9≠8, r9c9≠7, r7c9≠9, r7c9≠8, r7c9≠7
hidden-pairs-in-a-column: c4{n2 n4}{r4 r9} ==> r9c4≠9, r9c4≠8, r9c4≠7
whip[1]: b8n7{r9c6 .} ==> r1c6≠7
whip[1]: b8n8{r9c5 .} ==> r1c5≠8, r2c5≠8, r3c5≠8
naked-single ==> r3c5=1
whip[1]: b8n9{r9c6 .} ==> r1c6≠9
hidden-pairs-in-a-row: r1{n2 n4}{c1 c2} ==> r1c2≠9, r1c2≠8, r1c2≠7, r1c1≠9, r1c1≠8, r1c1≠7, r1c1≠6
extended tridagon for digits 7, 8 and 9 in blocks:
b3, with cells: r2c9 (link cell), r1c8, r3c7
b1, with cells: r2c2, r1c3 (link cell), r3c1
b9, with cells: r8c9, r7c8, r9c7
b7, with cells: r8c2, r7c1, r9c3
==> tridagon-link(n5r2c9, n6r1c3)


#80
Code: Select all
Resolution state after Singles and whips[1]:
   +-------------------+-------------------+-------------------+
   ! 3489  347   3467  ! 34678 3459  34678 ! 259   2589  1     !
   ! 189   17    167   ! 1678  159   2     ! 59    3     4     !
   ! 13489 2     5     ! 1348  1349  1348  ! 6     7     89    !
   +-------------------+-------------------+-------------------+
   ! 134   6     1347  ! 5     8     134   ! 12349 1249  2379  !
   ! 2     8     134   ! 1346  7     9     ! 1345  1456  356   !
   ! 5     1347  9     ! 2     134   1346  ! 134   1468  3678  !
   +-------------------+-------------------+-------------------+
   ! 134   9     8     ! 134   6     5     ! 7     124   23    !
   ! 6     134   2     ! 13478 134   13478 ! 13459 1459  359   !
   ! 7     5     134   ! 9     2     134   ! 8     146   36    !
   +-------------------+-------------------+-------------------+
181 candidates.

hidden-pairs-in-a-row: r8{n7 n8}{c4 c6} ==> r8c6≠4, r8c6≠3, r8c6≠1, r8c4≠4, r8c4≠3, r8c4≠1
extended tridagon for digits 1, 3 and 4 in blocks:
b5, with cells: r5c4 (link cell), r6c5, r4c6
b4, with cells: r5c3, r6c2 (link cell), r4c1
b8, with cells: r7c4, r8c5, r9c6
b7, with cells: r7c1, r8c2, r9c3
==> tridagon-link(n6r5c4, n7r6c2)


#81
Code: Select all
Resolution state after Singles and whips[1]:
   +-------------------+-------------------+-------------------+
   ! 3489  347   3467  ! 34678 3459  34678 ! 259   2589  1     !
   ! 189   17    167   ! 1678  159   2     ! 59    3     4     !
   ! 13489 2     5     ! 1348  1349  1348  ! 6     7     89    !
   +-------------------+-------------------+-------------------+
   ! 134   6     1347  ! 5     8     134   ! 12349 1249  2379  !
   ! 2     8     134   ! 1346  7     9     ! 1345  1456  356   !
   ! 5     1347  9     ! 2     134   1346  ! 134   1468  3678  !
   +-------------------+-------------------+-------------------+
   ! 134   9     8     ! 134   2     5     ! 7     146   36    !
   ! 6     134   2     ! 13478 134   13478 ! 13459 1459  359   !
   ! 7     5     134   ! 9     6     134   ! 8     124   23    !
   +-------------------+-------------------+-------------------+
181 candidates.

hidden-pairs-in-a-row: r8{n7 n8}{c4 c6} ==> r8c6≠4, r8c6≠3, r8c6≠1, r8c4≠4, r8c4≠3, r8c4≠1
extended tridagon for digits 1, 3 and 4 in blocks:
b5, with cells: r5c4 (link cell), r6c5, r4c6
b4, with cells: r5c3, r6c2 (link cell), r4c1
b8, with cells: r7c4, r8c5, r9c6
b7, with cells: r7c1, r8c2, r9c3
==> tridagon-link(n6r5c4, n7r6c2)
Last edited by denis_berthier on Sat Mar 19, 2022 7:38 am, edited 2 times in total.
denis_berthier
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Posts: 4189
Joined: 19 June 2007
Location: Paris

Re: The hardest sudokus (new thread)

Postby denis_berthier » Sat Mar 19, 2022 6:48 am

...
#102
Code: Select all
Resolution state after Singles and whips[1]:
   +----------------------+----------------------+----------------------+
   ! 34569  3789   345678 ! 56789  789    5789   ! 12789  12789  789    !
   ! 69     789    1      ! 6789   2      3      ! 789    4      5      !
   ! 59     789    2      ! 1      4      5789   ! 3      789    6      !
   +----------------------+----------------------+----------------------+
   ! 1239   13789  378    ! 23789  6      789    ! 4      5      789    !
   ! 239    5      378    ! 23789  789    4      ! 6      789    1      !
   ! 49     6      478    ! 789    5      1      ! 789    3      2      !
   +----------------------+----------------------+----------------------+
   ! 1356   4      356    ! 5789   1789   5789   ! 25789  26789  3789   !
   ! 7      13     356    ! 4589   189    2      ! 589    689    3489   !
   ! 8      2      9      ! 457    3      6      ! 157    17     47     !
   +----------------------+----------------------+----------------------+
180 candidates.

hidden-pairs-in-a-column: c4{n2 n3}{r4 r5} ==> r5c4≠9, r5c4≠8, r5c4≠7, r4c4≠9, r4c4≠8, r4c4≠7
hidden-pairs-in-a-row: r1{n1 n2}{c7 c8} ==> r1c8≠9, r1c8≠8, r1c8≠7, r1c7≠9, r1c7≠8, r1c7≠7
extended tridagon for digits 7, 8 and 9 in blocks:
b2, with cells: r3c6 (link cell), r2c4 (link cell), r1c5
b3, with cells: r3c8, r2c7, r1c9
b5, with cells: r4c6, r6c4, r5c5
b6, with cells: r4c9, r6c7, r5c8
==> tridagon-link(n5r3c6, n6r2c4)


#103
Code: Select all
Resolution state after Singles and whips[1]:
   +----------------------+----------------------+----------------------+
   ! 246789 24789  6789   ! 3789   3569   35678  ! 5789   789    1      !
   ! 16789  789    16789  ! 789    569    2      ! 3      4      5789   !
   ! 789    3      5      ! 789    1      4      ! 789    6      2      !
   +----------------------+----------------------+----------------------+
   ! 1289   2589   189    ! 23     7      135    ! 4      289    6      !
   ! 12467  2457   167    ! 24     8      9      ! 157    3      57     !
   ! 124789 245789 3      ! 6      245    15     ! 15789  2789   5789   !
   +----------------------+----------------------+----------------------+
   ! 789    1      2      ! 5      349    378    ! 6      789    34789  !
   ! 3      789    4      ! 1      69     678    ! 2      5      789    !
   ! 5      6      789    ! 234789 2349   378    ! 789    1      34789  !
   +----------------------+----------------------+----------------------+
187 candidates.

hidden-pairs-in-a-column: c9{n3 n4}{r7 r9} ==> r9c9≠9, r9c9≠8, r9c9≠7, r7c9≠9, r7c9≠8, r7c9≠7
hidden-pairs-in-a-row: r1{n2 n4}{c1 c2} ==> r1c2≠9, r1c2≠8, r1c2≠7, r1c1≠9, r1c1≠8, r1c1≠7, r1c1≠6
extended tridagon for digits 7, 8 and 9 in blocks:
b3, with cells: r2c9 (link cell), r1c8, r3c7
b1, with cells: r2c2, r1c3 (link cell), r3c1
b9, with cells: r8c9, r7c8, r9c7
b7, with cells: r8c2, r7c1, r9c3
==> tridagon-link(n5r2c9, n6r1c3)


#106
Code: Select all
Resolution state after Singles and whips[1]:
   +-------------------+-------------------+-------------------+
   ! 4589  457   456   ! 34579 4568  3456  ! 289   289   1     !
   ! 189   17    16    ! 179   168   2     ! 3     4     5     !
   ! 14589 2     3     ! 1459  1458  145   ! 6     7     89    !
   +-------------------+-------------------+-------------------+
   ! 12345 145   8     ! 145   9     1456  ! 1245  12356 7     !
   ! 145   6     7     ! 2     3     145   ! 14589 1589  489   !
   ! 12345 9     145   ! 8     1456  7     ! 1245  12356 2346  !
   +-------------------+-------------------+-------------------+
   ! 145   8     9     ! 6     2     1345  ! 7     135   34    !
   ! 6     3     145   ! 145   7     8     ! 12459 1259  249   !
   ! 7     145   2     ! 1345  145   9     ! 1458  13568 3468  !
   +-------------------+-------------------+-------------------+
180 candidates.

hidden-pairs-in-a-column: c1{n2 n3}{r4 r6} ==> r6c1≠5, r6c1≠4, r6c1≠1, r4c1≠5, r4c1≠4, r4c1≠1
extended tridagon for digits 1, 4 and 5 in blocks:
b8, with cells: r7c6 (link cell), r9c5, r8c4
b7, with cells: r7c1, r9c2, r8c3
b5, with cells: r5c6, r6c5 (link cell), r4c4
b4, with cells: r5c1, r6c3, r4c2
==> tridagon-link(n3r7c6, n6r6c5)


#118
Code: Select all
Resolution state after Singles and whips[1]:
   +----------------------+----------------------+----------------------+
   ! 246789 24789  6789   ! 789    3568   35679  ! 5789   789    1      !
   ! 16789  789    16789  ! 789    568    2      ! 3      4      5789   !
   ! 789    3      5      ! 789    1      4      ! 789    6      2      !
   +----------------------+----------------------+----------------------+
   ! 12469  2459   169    ! 24     7      8      ! 159    3      59     !
   ! 1278   2578   178    ! 3      9      15     ! 4      278    6      !
   ! 124789 245789 3      ! 6      245    15     ! 15789  2789   5789   !
   +----------------------+----------------------+----------------------+
   ! 789    1      2      ! 5      348    379    ! 6      789    34789  !
   ! 3      789    4      ! 1      68     679    ! 2      5      789    !
   ! 5      6      789    ! 24789  2348   379    ! 789    1      34789  !
   +----------------------+----------------------+----------------------+
182 candidates.

naked-pairs-in-a-column: c6{r5 r6}{n1 n5} ==> r1c6≠5
whip[1]: c6n5{r6 .} ==> r6c5≠5
hidden-pairs-in-a-column: c9{n3 n4}{r7 r9} ==> r9c9≠9, r9c9≠8, r9c9≠7, r7c9≠9, r7c9≠8, r7c9≠7
hidden-pairs-in-a-column: c4{n2 n4}{r4 r9} ==> r9c4≠9, r9c4≠8, r9c4≠7
whip[1]: b8n7{r9c6 .} ==> r1c6≠7
whip[1]: b8n8{r9c5 .} ==> r1c5≠8, r2c5≠8
whip[1]: b8n9{r9c6 .} ==> r1c6≠9
hidden-pairs-in-a-row: r1{n2 n4}{c1 c2} ==> r1c2≠9, r1c2≠8, r1c2≠7, r1c1≠9, r1c1≠8, r1c1≠7, r1c1≠6
extended tridagon for digits 7, 8 and 9 in blocks:
b3, with cells: r2c9 (link cell), r1c8, r3c7
b1, with cells: r2c2, r1c3 (link cell), r3c1
b9, with cells: r8c9, r7c8, r9c7
b7, with cells: r8c2, r7c1, r9c3
==> tridagon-link(n5r2c9, n6r1c3)


#121
Code: Select all
Resolution state after Singles and whips[1]:
   +----------------------+----------------------+----------------------+
   ! 489    469    479    ! 36789  5689   359    ! 259    25789  1      !
   ! 189    169    179    ! 6789   5689   2      ! 59     3      4      !
   ! 2      3      5      ! 14789  1489   149    ! 6      789    789    !
   +----------------------+----------------------+----------------------+
   ! 149    2      6      ! 1349   1459   7      ! 8      1459   359    !
   ! 3      149    8      ! 149    12459  1459   ! 7      12459  6      !
   ! 5      7      149    ! 134689 124689 1349   ! 12349  1249   239    !
   +----------------------+----------------------+----------------------+
   ! 149    5      2      ! 149    7      8      ! 1349   6      39     !
   ! 6      8      149    ! 2      3      149    ! 1459   14579  579    !
   ! 7      149    3      ! 5      149    6      ! 1249   12489  289    !
   +----------------------+----------------------+----------------------+
183 candidates.

hidden-pairs-in-a-row: r6{n6 n8}{c4 c5} ==> r6c5≠9, r6c5≠4, r6c5≠2, r6c5≠1, r6c4≠9, r6c4≠4, r6c4≠3, r6c4≠1
hidden-single-in-a-block ==> r5c5=2
extended tridagon for digits 1, 4 and 9 in blocks:
b5, with cells: r6c6 (link cell), r4c5 (link cell), r5c4
b4, with cells: r6c3, r4c1, r5c2
b8, with cells: r8c6, r9c5, r7c4
b7, with cells: r8c3, r9c2, r7c1
==> tridagon-link(n3r6c6, n5r4c5)


#123
Code: Select all
Resolution state after Singles and whips[1]:
   +----------------------+----------------------+----------------------+
   ! 26789  2459   4689   ! 389    379    369    ! 459    45789  1      !
   ! 6789   459    4689   ! 189    179    169    ! 459    2      3      !
   ! 13789  139    1389   ! 2      4      5      ! 6      789    789    !
   +----------------------+----------------------+----------------------+
   ! 123689 1239   13689  ! 7      139    4      ! 12359  1359   259    !
   ! 139    1349   5      ! 139    8      2      ! 7      1349   6      !
   ! 1239   7      1349   ! 5      6      139    ! 8      1349   249    !
   +----------------------+----------------------+----------------------+
   ! 139    8      7      ! 4      5      139    ! 1239   6      29     !
   ! 4      6      139    ! 139    2      7      ! 1359   13589  589    !
   ! 5      139    2      ! 6      139    8      ! 1349   13479  479    !
   +----------------------+----------------------+----------------------+
181 candidates
.
hidden-pairs-in-a-row: r4{n6 n8}{c1 c3} ==> r4c3≠9, r4c3≠3, r4c3≠1, r4c1≠9, r4c1≠3, r4c1≠2, r4c1≠1
extended tridagon for digits 1, 3 and 9 in blocks:
b4, with cells: r4c2 (link cell), r6c3 (link cell), r5c1
b5, with cells: r4c5, r6c6, r5c4
b7, with cells: r9c2, r8c3, r7c1
b8, with cells: r9c5, r8c4, r7c6
==> tridagon-link(n2r4c2, n4r6c3)


#126
Code: Select all
Resolution state after Singles and whips[1]:
   +-------------------+-------------------+-------------------+
   ! 3489  347   3467  ! 34678 3459  34678 ! 259   2589  1     !
   ! 189   17    167   ! 1678  159   2     ! 59    3     4     !
   ! 13489 2     5     ! 1348  1349  1348  ! 6     89    7     !
   +-------------------+-------------------+-------------------+
   ! 134   6     1347  ! 5     8     134   ! 12349 12479 239   !
   ! 2     8     134   ! 1346  7     9     ! 1345  1456  356   !
   ! 5     1347  9     ! 2     134   1346  ! 134   1467  8     !
   +-------------------+-------------------+-------------------+
   ! 134   9     8     ! 134   2     5     ! 7     146   36    !
   ! 6     134   2     ! 13478 134   13478 ! 13459 1459  359   !
   ! 7     5     134   ! 9     6     134   ! 8     124   23    !
   +-------------------+-------------------+-------------------+
177 candidates.

hidden-pairs-in-a-row: r8{n7 n8}{c4 c6} ==> r8c6≠4, r8c6≠3, r8c6≠1, r8c4≠4, r8c4≠3, r8c4≠1
extended tridagon for digits 1, 3 and 4 in blocks:
b5, with cells: r5c4 (link cell), r6c5, r4c6
b4, with cells: r5c3, r6c2 (link cell), r4c1
b8, with cells: r7c4, r8c5, r9c6
b7, with cells: r7c1, r8c2, r9c3
==> tridagon-link(n6r5c4, n7r6c2)


#139
Code: Select all
Resolution state after Singles and whips[1]:
   +----------------------+----------------------+----------------------+
   ! 489    469    479    ! 36789  5689   359    ! 259    25789  1      !
   ! 189    169    179    ! 6789   5689   2      ! 59     3      4      !
   ! 2      3      5      ! 14789  1489   149    ! 6      789    789    !
   +----------------------+----------------------+----------------------+
   ! 149    2      6      ! 1349   1459   7      ! 8      1459   359    !
   ! 3      149    8      ! 149    2      1459   ! 7      1459   6      !
   ! 5      7      149    ! 134689 14689  1349   ! 1349   149    2      !
   +----------------------+----------------------+----------------------+
   ! 149    5      12349  ! 149    7      8      ! 12349  6      39     !
   ! 6      8      149    ! 2      3      149    ! 1459   14579  579    !
   ! 7      149    12349  ! 5      149    6      ! 12349  12489  389    !
   +----------------------+----------------------+----------------------+
183 candidates.

hidden-pairs-in-a-column: c3{n2 n3}{r7 r9} ==> r9c3≠9, r9c3≠4, r9c3≠1, r7c3≠9, r7c3≠4, r7c3≠1
hidden-pairs-in-a-row: r6{n6 n8}{c4 c5} ==> r6c5≠9, r6c5≠4, r6c5≠1, r6c4≠9, r6c4≠4, r6c4≠3, r6c4≠1
extended tridagon for digits 1, 4 and 9 in blocks:
b5, with cells: r6c6 (link cell), r4c5 (link cell), r5c4
b4, with cells: r6c3, r4c1, r5c2
b8, with cells: r8c6, r9c5, r7c4
b7, with cells: r8c3, r9c2, r7c1
==> tridagon-link(n3r6c6, n5r4c5)


#146
Code: Select all
Resolution state after Singles and whips[1]:
   +-------------------+-------------------+-------------------+
   ! 3457  3468  3479  ! 3489  347   346   ! 589   1     2     !
   ! 1257  1268  279   ! 289   27    26    ! 3     58    4     !
   ! 234   2348  2349  ! 23489 1     5     ! 6     7     89    !
   +-------------------+-------------------+-------------------+
   ! 2347  234   8     ! 12345 9     234   ! 12457 2345  6     !
   ! 234   5     1     ! 234   6     7     ! 2489  2348  389   !
   ! 6     9     2347  ! 12345 234   8     ! 12457 2345  1357  !
   +-------------------+-------------------+-------------------+
   ! 1234  7     5     ! 234   8     9     ! 124   6     13    !
   ! 8     1234  234   ! 6     5     234   ! 1247  9     137   !
   ! 9     234   6     ! 7     234   1     ! 2458  23458 358   !
   +-------------------+-------------------+-------------------+
176 candidates.

hidden-pairs-in-a-column: c4{n1 n5}{r4 r6} ==> r6c4≠4, r6c4≠3, r6c4≠2, r4c4≠4, r4c4≠3, r4c4≠2
extended tridagon for digits 2, 3 and 4 in blocks:
b7, with cells: r7c1 (link cell), r8c3, r9c2
b8, with cells: r7c4, r8c6, r9c5
b4, with cells: r5c1, r6c3 (link cell), r4c2
b5, with cells: r5c4, r6c5, r4c6
==> tridagon-link(n1r7c1, n7r6c3)


#147
Code: Select all
Resolution state after Singles and whips[1]:
   +-------------------+-------------------+-------------------+
   ! 3457  3468  3479  ! 3489  346   347   ! 589   1     2     !
   ! 1257  1268  279   ! 289   26    27    ! 3     58    4     !
   ! 234   2348  2349  ! 23489 1     5     ! 6     7     89    !
   +-------------------+-------------------+-------------------+
   ! 2347  234   8     ! 12345 9     234   ! 12457 2345  6     !
   ! 234   5     1     ! 234   7     6     ! 2489  2348  389   !
   ! 6     9     2347  ! 12345 234   8     ! 12457 2345  1357  !
   +-------------------+-------------------+-------------------+
   ! 1234  7     5     ! 234   8     9     ! 124   6     13    !
   ! 8     1234  234   ! 6     5     234   ! 1247  9     137   !
   ! 9     234   6     ! 7     234   1     ! 2458  23458 358   !
   +-------------------+-------------------+-------------------+
176 candidates.

hidden-pairs-in-a-column: c4{n1 n5}{r4 r6} ==> r6c4≠4, r6c4≠3, r6c4≠2, r4c4≠4, r4c4≠3, r4c4≠2
extended tridagon for digits 2, 3 and 4 in blocks:
b7, with cells: r7c1 (link cell), r8c3, r9c2
b8, with cells: r7c4, r8c6, r9c5
b4, with cells: r5c1, r6c3 (link cell), r4c2
b5, with cells: r5c4, r6c5, r4c6
==> tridagon-link(n1r7c1, n7r6c3)

#177
Code: Select all
Resolution state after Singles and whips[1]:
   +-------------------+-------------------+-------------------+
   ! 4589  457   456   ! 34579 4568  3456  ! 29    289   1     !
   ! 189   17    16    ! 179   168   2     ! 3     4     5     !
   ! 14589 2     3     ! 1459  1458  145   ! 6     7     89    !
   +-------------------+-------------------+-------------------+
   ! 12345 145   8     ! 145   9     1456  ! 1245  12356 7     !
   ! 145   6     7     ! 2     3     145   ! 1459  1589  489   !
   ! 12345 9     145   ! 8     1456  7     ! 1245  12356 2346  !
   +-------------------+-------------------+-------------------+
   ! 145   8     9     ! 6     2     1345  ! 7     135   34    !
   ! 6     3     145   ! 145   7     8     ! 12459 1259  249   !
   ! 7     145   2     ! 1345  145   9     ! 8     1356  346   !
   +-------------------+-------------------+-------------------+
172 candidates.

hidden-pairs-in-a-column: c1{n2 n3}{r4 r6} ==> r6c1≠5, r6c1≠4, r6c1≠1, r4c1≠5, r4c1≠4, r4c1≠1
extended tridagon for digits 1, 4 and 5 in blocks:
b8, with cells: r7c6 (link cell), r9c5, r8c4
b7, with cells: r7c1, r9c2, r8c3
b5, with cells: r5c6, r6c5 (link cell), r4c4
b4, with cells: r5c1, r6c3, r4c2
==> tridagon-link(n3r7c6, n6r6c5)


#192
Code: Select all
Resolution state after Singles and whips[1]:
   +----------------------+----------------------+----------------------+
   ! 489    469    479    ! 36789  5689   359    ! 259    25789  1      !
   ! 189    169    179    ! 6789   5689   2      ! 59     3      4      !
   ! 2      3      5      ! 14789  1489   149    ! 6      789    789    !
   +----------------------+----------------------+----------------------+
   ! 149    2      6      ! 1349   1459   7      ! 8      1459   359    !
   ! 3      149    8      ! 149    2      1459   ! 7      1459   6      !
   ! 5      7      149    ! 134689 14689  1349   ! 12349  1249   239    !
   +----------------------+----------------------+----------------------+
   ! 149    5      2      ! 149    7      8      ! 1349   6      39     !
   ! 6      8      149    ! 2      3      149    ! 1459   14579  579    !
   ! 7      149    3      ! 5      149    6      ! 1249   12489  289    !
   +----------------------+----------------------+----------------------+
176 candidates.

hidden-pairs-in-a-row: r6{n6 n8}{c4 c5} ==> r6c5≠9, r6c5≠4, r6c5≠1, r6c4≠9, r6c4≠4, r6c4≠3, r6c4≠1
extended tridagon for digits 1, 4 and 9 in blocks:
b5, with cells: r6c6 (link cell), r4c5 (link cell), r5c4
b4, with cells: r6c3, r4c1, r5c2
b8, with cells: r8c6, r9c5, r7c4
b7, with cells: r8c3, r9c2, r7c1
==> tridagon-link(n3r6c6, n5r4c5)

#217
Code: Select all
Resolution state after Singles and whips[1]:
   +----------------------+----------------------+----------------------+
   ! 234569 25789  24569  ! 356789 3789   789    ! 789    4789   1      !
   ! 4569   5789   4569   ! 56789  789    1      ! 2      3      4789   !
   ! 39     789    1      ! 3789   2      4      ! 5      789    6      !
   +----------------------+----------------------+----------------------+
   ! 12459  259    3      ! 4789   1789   789    ! 6      124789 45789  !
   ! 149    6      49     ! 34789  5      2      ! 3789   14789  4789   !
   ! 7      259    8      ! 349    139    6      ! 39     1249   459    !
   +----------------------+----------------------+----------------------+
   ! 289    1      279    ! 789    6      5      ! 4      789    3      !
   ! 689    3      679    ! 2      4      789    ! 1      5      789    !
   ! 589    4      579    ! 1      789    3      ! 789    6      2      !
   +----------------------+----------------------+----------------------+
179 candidates.

hidden-pairs-in-a-column: c4{n5 n6}{r1 r2} ==> r2c4≠9, r2c4≠8, r2c4≠7, r1c4≠9, r1c4≠8, r1c4≠7, r1c4≠3
extended tridagon for digits 7, 8 and 9 in blocks:
b2, with cells: r3c4 (link cell), r2c5, r1c6
b3, with cells: r3c8, r2c9 (link cell), r1c7
b8, with cells: r7c4, r9c5, r8c6
b9, with cells: r7c8, r9c7, r8c9
==> tridagon-link(n3r3c4, n4r2c9)


The only two that don't have a tridagon elimination or a tridagon link between two candidates are #7 and #38
Last edited by denis_berthier on Sat Mar 19, 2022 7:49 am, edited 1 time in total.
denis_berthier
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Re: The hardest sudokus (new thread)

Postby marek stefanik » Sat Mar 19, 2022 7:06 am

Edit: no longer relevant, missed your edit
Last edited by marek stefanik on Sat Mar 19, 2022 7:09 am, edited 1 time in total.
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