The New Sudoku Players' Forum

[Draco]

This one was in the 9 May 2009 Seattle Times; tougher than puzzles theyh run. It even has an XYZ-Wing near the end (though not requried to crack it). Too much for my manual solving skills, but it might make a tasty morsel for those looking for something more challanging than standard newspaper fare, without being too hard. Interesting symmetry as well:

Code: Select all

.97.....62....31...6....75..1..476.....9.6.....625..4..45....3...91....88.....57.

1345 9     7    | 458   128   12458 | 2348 28  6   
2    58    48   | 45678 6789  3     | 1    89  49   
134  6     1348 | 48    1289  12489 | 7    5   2349
----------------+-------------------+---------------
359  1     238  | 38    4     7     | 6    289 2359
3457 23578 2348 | 9     138   6     | 238  128 12357
379  378   6    | 2     5     18    | 389  4   1379
----------------+-------------------+---------------
167  4     5    | 678   26789 289   | 29   3   129 
367  237   9    | 1     2367  245   | 24   26  8   
8    23    123  | 346   2369  249   | 5    7   1249

Cheers...

- drac

[udosuk]

Depending on opinions, I think W-wing & XY-wing are marginally acceptable for printed puzzles which encourage people to solve with pencilmarks.

Code: Select all

+------------------+------------------+------------------+
|#134   9     7    | 5     128  #248  | 238   28    6    |
| 2     5    *48   | 67    67    3    | 1     89    49   |
| 134   6    -834  |*48    1289  2489 | 7     5     234  |
+------------------+------------------+------------------+
| 359   1     23   | 38    4     7    | 6     289   2359 |
| 3457  378   234  | 9     38    6    | 238   1     2357 |
| 379   378   6    | 2     5     1    | 389   4     379  |
+------------------+------------------+------------------+
| 6     4     5    | 78    2789  289  | 29    3     1    |
| 37    237   9    | 1     23    5    | 4     6     8    |
| 8     23    1    | 346   2369  249  | 5     7     29   |
+------------------+------------------+------------------+

W-wing:
4 @ r1 locked @ r1c16
r2c3 & r3c4 are from {48}
=> at least one of r2c3+r3c4 must be 8
=> r3c3, seeing r2c3+r3c4, can't be 8

XY-wing:
r3c4 must be 4 or 8
r3c3 must be 3 or 4
r4c4 must be 3 or 8
=> at least one of r3c3+r4c4 must be 3
=> r4c3, seeing r3c3+r4c4, can't be 3, must be 2

Also, the symmetry is plainly 180 degree rotational, couldn't see the "interesting" point...

[Draco]

I thought the shape of the digit layout was interesting; should've said that more plainly.

Cheers...

- drac