HoDoKu Solving Technique Index: Example for "XY-Chain"

Solving Technique Example

Original sudoku:

3...4.52858.........2..........74....1....35..5.6...4..78.....21..2......39..68..

Use the following line if you want to load the sudoku in HoDoKu:

:0702:3:3+6+1+74+952858+4...+7+9.+7+92.....+4+9+2+3+574.+8.+41+6...35+7+85+76+3+1+24+9+678...+4+121+4+52+8+7+9..+239+4+168+7+5::324 334 376:

The following representation can be pasted in most Sudoku programs:

.---------.--------------.-------------.

| 3  6  1 | 7    4   9   | 5   2   8   |

| 5  8  4 | 13   26  23  | 7   9   136 |

| 7  9  2 | 138  56  358 | 16  36  4   |

:---------+--------------+-------------:

| 9  2  3 | 5    7   4   | 16  8   16  |

| 4  1  6 | 89   29  28  | 3   5   7   |

| 8  5  7 | 6    3   1   | 2   4   9   |

:---------+--------------+-------------:

| 6  7  8 | 39   59  35  | 4   1   2   |

| 1  4  5 | 2    8   7   | 9   36  36  |

| 2  3  9 | 4    1   6   | 8   7   5   |

'---------'--------------'-------------'

Representation of the step:

.---------.-----------------.-------------.

| 3  6  1 |  7     4    9   | 5   2   8   |

| 5  8  4 |  1-3   26  *23  | 7   9   136 |

| 7  9  2 |  1-38  56   358 | 16  36  4   |

:---------+-----------------+-------------:

| 9  2  3 |  5     7    4   | 16  8   16  |

| 4  1  6 | *89    29  *28  | 3   5   7   |

| 8  5  7 |  6     3    1   | 2   4   9   |

:---------+-----------------+-------------:

| 6  7  8 | *39    59  -35  | 4   1   2   |

| 1  4  5 |  2     8    7   | 9   36  36  |

| 2  3  9 |  4     1    6   | 8   7   5   |

'---------'-----------------'-------------'



XY-Chain 3- r7c4 -9- r5c4 -8- r5c6 -2- r2c6 -3 => r23c4,r7c6<>3