The New Sudoku Players' Forum

[Pat]

The Superior thread has many examples of puzzles requiring several X-wings, hidden triples.

I posted one with 2 hidden triples
& if I recall correctly, gsf posted one with 3 X-wings.

well find them and post them here -- but remember, for Eioru's scoring, we must add up the scores for all the possible lesser moves, thus 3 X-wings may score lower than 2 X-wings---


also note, Nicolas Juillerat [ Sudoku Explainer ] uses his own scale of difficulty
which does not match the definitions for "superior" puzzles

e.g. he'll use Swordfish ahead of a "hidden" trio

[tarek]

what Ill do is find the puzzles & post them with SE121 comments

tarek

[tarek]

I forgot to say that you can compile SE121 & change the method heirarchy or scoring (I have done that due to the patterns game prior to gsf's version)

tarek

[JPF]

From the Patterns Game, maybe a good candidate for ER=8.2

Code: Select all

 . . 1 | 2 . . | . . .
 . 3 . | . . 4 | 5 . .
 6 . . | . . . | . 7 .
-------+-------+-------
 7 . . | 6 . . | . 2 .
 . . . | . . . | . . .
 . 8 . | . . 3 | . . 4
-------+-------+-------
 . 4 . | . . . | . . 5
 . . 2 | 1 . . | . 6 .
 . . . | . . 8 | 3 . .       



This Sudoku can be solved using the following logical methods:
58 x Hidden Single
2 x Naked Single
1 x Direct Hidden Triplet
5 x Pointing
3 x Claiming
3 x Naked Pair
1 x X-Wing
1 x Naked Triplet
2 x Swordfish
1 x XY-Wing
1 x Forcing X-Chain
4 x Bidirectional Cycle
43 x Forcing Chain
1 x Nishio Forcing Chains
4 x Region Forcing Chains

JPF

[tarek]

From the 100 superiors, the ones I thought would be striking gave these results.

...........4.8.1...8.6.7.5.95.2.8.472...6...371.4.3.29.6.8.2.3...1.9.4...........
Difficulty rating: 3.2
This Sudoku can be solved using the following logical methods: 48 x Hidden Single 4 x Direct Hidden Pair 1 x Claiming 1 x Naked Pair 1 x X-Wing

.2.....3...7.2.1....96.82...6.7.5.2...5...8...9.2.1.6...28.65....1.7.9...5.....1.
Difficulty rating: 3.2
This Sudoku can be solved using the following logical methods: 52 x Hidden Single 1 x Direct Hidden Pair 4 x X-Wing

.5.....6....7.4.....8.2.9..3..4.2..9.29...65.4..9.5..7..1.3.2.....8.7....6.....3.
Difficulty rating: 3.6
This Sudoku can be solved using the following logical methods: 52 x Hidden Single 2 x Direct Hidden Pair 1 x Naked Single 2 x Pointing 2 x Naked Pair 3 x X-Wing 2 x Hidden Pair 1 x Naked Triplet

..25.74..6..9.3..8....1....9.4...5.28.......92.3...8.7....9....7..8.6..3..87.26..
Difficulty rating: 3.4
This Sudoku can be solved using the following logical methods: 52 x Hidden Single 1 x Direct Hidden Pair 3 x Pointing 4 x X-Wing 1 x Hidden Pair

.1.7.8.4.6...1...2.4.....8..6.5.2.3.2...9...4.9.3.1.2..2.....6.9...6...5.3.8.5.9.
Difficulty rating: 3.2
This Sudoku can be solved using the following logical methods: 49 x Hidden Single 3 x Direct Hidden Pair 2 x Pointing 1 x Naked Pair 4 x X-Wing

..8...6.....931...5.......3.2..1..9..8.4.5.3..6..7..1.9.......4...142.....7...5..
Difficulty rating: 4.0
This Sudoku can be solved using the following logical methods: 57 x Hidden Single 11 x Pointing 2 x Claiming 1 x Naked Pair 1 x Hidden Pair 3 x Hidden Triplet

.........14..7......51.69...21..5.8.4.......7.8.7..62...93.45......2..18.........
Difficulty rating: 3.2
This Sudoku can be solved using the following logical methods: 52 x Hidden Single 4 x Direct Hidden Pair 1 x Naked Single 3 x Pointing 1 x Claiming 3 x X-Wing

4.......7..3...2...7.6.3.9...6.8.7.....9.5.....2.4.9...5.3.4.8...7...6..8.......5
Difficulty rating: 3.2
This Sudoku can be solved using the following logical methods: 55 x Hidden Single 2 x Direct Hidden Pair 4 x Pointing 1 x Claiming 2 x Naked Pair 3 x X-Wing

..46....52....4.7..9...84...65....1....8.1....4....68...72...5..8.1....34....91..
Difficulty rating: 3.2
This Sudoku can be solved using the following logical methods: 52 x Hidden Single 3 x Direct Hidden Pair 1 x Naked Pair 3 x X-Wing

.5.....1.2.......6.196.452...1.7.2..6..4.9..3..3.5.6...645.297.8.......2.7.....6.
Difficulty rating: 3.2
This Sudoku can be solved using the following logical methods: 48 x Hidden Single 2 x Direct Hidden Pair 1 x Naked Single 3 x Pointing 2 x Claiming 4 x X-Wing

....4......86.29...5.8.1.4..43...85.2...1...3.85...62..2.7.9.3...94.62......2....
Difficulty rating: 4.0
This Sudoku can be solved using the following logical methods: 50 x Hidden Single 2 x Direct Hidden Pair 3 x Pointing 2 x X-Wing 2 x Hidden Triplet

6.45.27.9.........9..7.8..28.32.41.7.........7.91.52.83..4.1..6.........2.79.38.4
Difficulty rating: 2.5
This Sudoku can be solved using the following logical methods: 47 x Hidden Single 1 x Direct Hidden Pair 1 x Direct Hidden Triplet

tarek

[Eioru]

add 6.6 Bidirectional X-Cycle (8 cells)

Code: Select all

183456297
9642.7.53
.2.......
24.....71
.3..2....
65.....29
.1....932
492531768
37.9.2415

This puzzle has Bidirectional X-Cycle with 8 at H3, H5, A5, A7, C9, E9, E2 and G2 cells.

[tarek]

add 6.6 Bidirectional X-Cycle (8 cells)

Code: Select all

183456297
9642.7.53
.2.......
24.....71
.3..2....
65.....29
.1....932
492531768
37.9.2415

This puzzle has Bidirectional X-Cycle with 8 at H3, H5, A5, A7, C9, E9, E2 and G2 cells.

Also,
A very nice finned swordfish

Code: Select all

*--------------------------------------------------------*
| 1     8     3    | 4     5     6    | 2     9     7    |
| 9     6     4    | 2    *18    7    |*18    5     3    |
| 57    2     57   | 38    189   389  | 168   48    46   |
|------------------+------------------+------------------|
| 2     4     89   | 368   6-89  3589 | 3568  7     1    |
| 78    3     1789 | 1678  2     589  | 568   48    46   |
| 6     5    *178  |#1378  47   #348  | *38   2     9    |
|------------------+------------------+------------------|
| 58    1     568  | 678   47    48   | 9     3     2    |
| 4     9     2    | 5     3     1    | 7     6     8    |
| 3     7    *68   | 9    *68    2    | 4     1     5    |
*--------------------------------------------------------*
Eliminating 8 From r4c5 (Finned Swordfish in Rows 269 with 2 fins in Box 5)
*--------------------------------------------------------*
| 1     8     3    | 4     5     6    | 2     9     7    |
| 9     6     4    | 2     18    7    | 18    5     3    |
| 57    2     57   | 38    189   389  | 168   48    46   |
|------------------+------------------+------------------|
| 2     4    *89   | 368  *69    3589 | 3568  7     1    |
| 78    3     1789 | 1678  2     589  | 568   48    46   |
| 6     5     178  | 1378  47    348  | 38    2     9    |
|------------------+------------------+------------------|
| 58    1     568  | 678   47    48   | 9     3     2    |
| 4     9     2    | 5     3     1    | 7     6     8    |
| 3     7    *68   | 9    -68    2    | 4     1     5    |
*--------------------------------------------------------*
Eliminating 6 From r9c5 (9 & 8 in r4c3 form an XY wing with 6 in r4c5 & r9c3)

tarek

[999_Springs]

From what I have seen here, it seems that SE finds unique loops with 12 cells.
So why doesn't it find this?

Code: Select all

#4 from the top95

4   8     7  |3   12   12  |56 9  56
59  59    3  |6   48   48  |2  7  1
1   2     6  |57  9    57  |3  8  4
-------------+-------------+--------
7   34    5  |89  348  489 |1  6  2
69  13469 49 |2   1346 57  |8  34 57
28  1346  28 |57  1346 14  |57 34 9
-------------+-------------+--------
58  45    1  |48  7    6   |9  2  3
3   67    89 |1   28   289 |4  5  67
269 4679  249|49  5    3   |67 1  8

12-cell UL: r1c79, r3c46, r5c69, r6c47, r8c29, r9c27 => r9c2<>67

This is the same puzzle as the one I posted here with the additional clue 3 in r2c3. re'born spotted the BUG-Lite.

[Glyn]

999_Springs I have had a quick look at the source code and found that the Unique loops identifiable by SE are restricted to 2 digits.

The case you have found uses 3 digits 5,6,7. This is a more difficult problem. Well spotted.