The New Sudoku Players' Forum

[m_b_metcalf]

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 . 1 2 3 4 5 . . .
 . 6 . . . . 1 . .
 . 7 . . . . . 2 .
 . 5 . . . . . 6 .
 . 2 . . . . . 4 .
 . 8 . . . . . 1 .
 . 9 . . . . . 7 .
 . 4 . . . . 9 . .
 . 3 7 6 2 9 . . .   fairly hard

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

[Leren]

Both puzzles were solved without recourse to forcing chains. I've printed this easy move from the second puzzle because it is not in Andrew Stuart's Sudoku X solver.

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*----------------------------------------------------*
|A89    1 2     | 3     4     5    | 6    B89   7    |
| 34589 6 34589 | 2789  789   278  | 1     3589 3458 |
| 34589 7 3589  | 189   1689  168  | 358   2    3458 |
|---------------+------------------+-----------------|
| 3479  5 1349  | 14789 1389  1238 | 378   6    2389 |
| 13679 2 139   | 1589  589   1368 | 3578  4    3589 |
| 34679 8 349   | 259   3569  347  | 357   1    2359 |
|---------------+------------------+-----------------|
| 158   9 6     | 1458  1358  1348 | 2     7    1358 |
| 2     4 158   | 1578  13578 1378 | 9     35-8 6    |
| 158   3 7     | 6     2     9    | 4     58   158  |
*----------------------------------------------------*

(8) r1c1 = (8) r1c8 => - 8 r8c8

This is the other way of looking at pointing pairs on a Diagonal, which is one of the most basic X moves, and Andrew does implement.

Leren

[Pat]

this easy move from the {first} puzzle
is not in Andrew Stuart's Sudoku X solver.

Code: Select all

*----------------------------------------------------*
|A89    1 2     | 3     4     5    | 6    B89   7    |
| 34589 6 34589 | 2789  789   278  | 1     3589 3458 |
| 34589 7 3589  | 189   1689  168  | 358   2    3458 |
|---------------+------------------+-----------------|
| 3479  5 1349  | 14789 1389  1238 | 378   6    2389 |
| 13679 2 139   | 1589  589   1368 | 3578  4    3589 |
| 34679 8 349   | 259   3569  347  | 357   1    2359 |
|---------------+------------------+-----------------|
| 158   9 6     | 1458  1358  1348 | 2     7    1358 |
| 2     4 158   | 1578  13578 1378 | 9     35-8 6    |
| 158   3 7     | 6     2     9    | 4     58   158  |
*----------------------------------------------------*

(8) r1c1 = (8) r1c8 => - 8 r8c8

This is the other way of looking at pointing pairs on a Diagonal, which is one of the most basic X moves, and Andrew does implement.

Leren

it is actually a
"finned" fish of order 1:

(8) r1\c8 with "fin" = r1c1