The New Sudoku Players' Forum

[m_b_metcalf]

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 . 1 2 3 4 5 6 7 8
 . . . . 6 7 . . .
 . . . . 9 1 . . .
 . . . . 7 2 . . .
 . . . . 1 9 . . .
 . . . . 3 8 . . .
 . . . . 8 3 . . .
 . . . . 2 4 . . .
 . . . 7 5 6 3 . .   easy

 . 1 2 3 4 5 6 7 8
 . . . . 6 7 . . .
 . . . . 9 8 . . .
 . . . . 7 2 . . .
 . . . . 1 9 . . .
 . . . . 3 4 . . .
 . . . . 5 3 . . .
 . . . . 2 1 . . .
 . . . 7 8 6 3 . .   not very hard

M

[Leren]

Both easy. Perhaps it was the T pattern that was hard to make a hard puzzle.

Leren

[m_b_metcalf]

Both easy. Perhaps it was the T pattern that was hard to make a hard puzzle.

This what I think of as a very 'stiff' pattern, and it was not trivial to find any examples. Here's another one:

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 . 1 2 3 4 5 6 7 8
 . . . . 6 7 . . .
 . . . . 2 8 . . .
 . . . . 7 2 . . .
 . . . . 1 9 . . .
 . . . . 3 4 . . .
 . . . . 9 3 . . .
 . . . . 5 1 . . .
 . . . 7 8 6 3 . .   my hardest

Perhaps Hajime can do better.

Mike

[Leren]

Hi Mike,

Harder but no forcing chains. Can't wait for the X pattern. That may be interesting one way or another.

Leren

[Hajime]

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 . 1 2 3 4 5 6 7 8
 . . . . 6 7 . . .
 . . . . 2 8 . . .
 . . . . 7 2 . . .
 . . . . 1 9 . . .
 . . . . 3 4 . . .
 . . . . 9 3 . . .
 . . . . 5 1 . . .
 . . . 7 8 6 3 . .   my hardest

Perhaps Hajime can do better.

Only 0.1 better:

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.98345716....67.......28.......72.......19.......34.......93.......51......4863..   ED=7.3/1.0/1.0

Indeed very hard to find puzzles. In the night only 11 puzzles with 6 different ED's :

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ED=2.0/1.0/1.0 , 2.5/1.0/1.0 , 2.9/1.0/1.0 , 3.0/1.0/1.0 , 7.2/1.0/1.0 , 7.3/1.0/1.0

Thank you Mike for this sequence of puzzles.

[m_b_metcalf]

Perhaps Hajime can do better.

Only 0.1 better:

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.98345716....67.......28.......72.......19.......34.......93.......51......4863..   ED=7.3/1.0/1.0

Indeed very hard to find puzzles. In the night only 6 different ED's :

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ED=2.0/1.0/1.0 , 2.5/1.0/1.0 , 2.9/1.0/1.0 , 3.0/1.0/1.0 , 7.2/1.0/1.0 , 7.3/1.0/1.0

I can add only these additional ratings:

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.12345678....67.......98.......72.......19.......34.......83.......21......7563..   ED=2.3/1.0/1.0   
.12345678....67.......28.......79.......12.......36.......53.......91......7843..   ED=6.3/1.0/1.0   
.12345678....67.......28.......72.......19.......34.......93.......81......7563..   ED=6.6/1.0/1.0   

jpf remains our only hope for a higher rating.

Thank you Mike for this sequence of puzzles.

You're most welcome!

[Mathimagics]

Hmmm .....

I do have an issue with that pattern !

Since T is a very elementary letter shape, would it not be unreasonable to ask for some consistency regarding the serif attribute?

This would be appropriate, IMHO:

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 . X X X X X X X X
 . X . . X X . . X
 . . . . X X . . .
 . . . . X X . . .
 . . . . X X . . .
 . . . . X X . . .
 . . . . X X . . .
 . . . . X X . . .
 . . . X X X X . .


Or, simply remove the serif in row 9 (c47) for a true sans serif "T". Mixing of the two forms is generally frowned upon by the International Brotherhood of Typesetters.

[Hajime]

Hi MM, because r1c1= 'naked single' no pearls and diamonds to be found

[m_b_metcalf]

I do have an issue with that pattern !

Dear MM, so do I. My basic goal was to produce only sans serif letters, but for T I failed. In fact, in order get the pattern I posted, I had to start off with exactly the shape you propose and progressively remove the serif clues. However, I couldn't remove all four, but only either one of the two pairs.

Regards,

Mike

P.S. I wasn't looking necessarily for high-rated puzzles, more for ones that are suitable for human solvers.

[urhegyi]

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.9584731.
....96...
....25...
....18...
....74...
....53...
....82...
....69...
...5318..

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.9584731.....96.......25.......18.......74.......53.......82.......69......5318.. ED=7.1/2.0/2.0

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checked with sisesuso: even with generalized intersections disabled it finds a solution without forcing chains

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Summary eliminated candidates per Method And per Sudoku

Method   \  Sudoku |   SER |     1 (#Methods)
                   |-------|---------------
Solved Clue elims  |     0 |   139 (139)
Naked Singles      |   0.1 |    44 (44)
Hidden Singles     |   0.2 |    46 (12)
Naked Pair     [2] |     3 |     4 (3)
Naked Quad     [4] |     5 |     6 (2)
Hidden Quad    [5] |   5.4 |    14 (4)
Hidden Triple  [6] |     4 |     2 (1)
Pointing/Claiming  |   2.8 |    13 (13)
WXYZ Wing     [B4] |   5.5 |     1 (1)
Turbot-fish    [4] |   4.2 |     7 (7)
X-chain        [6] |   5.4 |     1 (1)
XY-chain       [2] |   3.6 |     3 (3)
XY-Wing        [3] |   4.1 |     1 (1)
XY-chain       [4] |   4.6 |     1 (1)
XY-chain       [5] |   5.1 |     1 (1)
                   |-------|---------------
Eliminated Cand's  |   283 |   283
Sum(SER * Cand's)  | 240.5 | 240.5

Initial Candidates :   283
Maximum SER rating :   5.5 <- Approach
Labour rating      : 240.5 <- Experimental rating
Time needed        : 00:00:03.375
SiSeSuSo Solver and Generator (version 2023-03)

[urhegyi]

When I can find examples with R1C2 removed they are symmetric like the original one.
Here are the hardest ones:

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..584631.....97.......25.......18.......74.......53.......82.......69......5318.. ED=4.2/1.5/1.5
..584731.....96.......25.......58.......73.......19.......82.......64......5314.. ED=4.5/2.0/2.0
..582631.....93.......45.......18.......74.......59.......82.......67......5318.. ED=7.1/1.5/1.5
..582741.....96.......45.......18.......64.......53.......82.......79......5318.. ED=7.1/1.5/1.5


[Hajime]

MM's hardest sofar:

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.76145823.5..67..4....28.......72.......19.......34.......93.......81......4563..   ED=9.0/1.0/1.0

[1to9only]

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 . 1 2 3 4 5 7 6 8
 . . . . 6 7 . . .
 . . . . 2 1 . . .
 . . . . 3 4 . . .
 . . . . 7 9 . . .
 . . . . 1 8 . . .
 . . . . 8 3 . . .
 . . . . 9 2 . . .
 . . . 1 5 6 3 . . ED=8.3/1.0/1.0


[urhegyi]

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 . 1 2 3 4 5 7 6 8
 . . . . 6 7 . . .
 . . . . 2 1 . . .
 . . . . 3 4 . . .
 . . . . 7 9 . . .
 . . . . 1 8 . . .
 . . . . 8 3 . . .
 . . . . 9 2 . . .
 . . . 1 5 6 3 . . ED=8.3/1.0/1.0


Inspired by yours,

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.12345678....68.......29.......82.......31.......74.......17.......93......8567.. ED=4.0/1.0/1.0
.12345678....21.......76.......84.......19.......63.......38.......97......6527.. ED=7.2/1.0/1.0
.12345678....76.......12.......94.......68.......23.......39.......81......2574.. ED=8.3/1.0/1.0
.12345678....21.......86.......94.......17.......63.......39.......78......4527.. ED=8.3/1.0/1.0


[1to9only]

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.29345176....87.......61.......72.......19.......36.......53.......24......7983.. ED=7.6/1.0/1.0
.29345176....67.......81.......32.......19.......76.......53.......24......7983.. ED=7.8/1.0/1.0
.12345678....67.......91.......72.......59.......38.......23.......14......5863.. ED=8.5/1.0/1.0
.29345176....67.......81.......72.......58.......39.......13.......26......5943.. ED=8.9/1.0/1.0
.29345678....87.......61.......72.......59.......34.......13.......28......7961.. ED=9.0/1.0/1.0