HoDoKu Solving Technique Index: Example for "ALS-XY-Wing"

Solving Technique Example

Original sudoku:

4.6....7......1.6.....8....23..........34.......8..95..9.........2.5761.5...2...4

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

:9002:3:4.6....7......1+46....+68+4...23.....+4....34.......8.+295+3.9.......+3.2.5761.5...2...4:812 914 721 722 723 924 829 133 733 143 743 144 944 849 852 153 753 859 171 773 873 175 893 996:377:

The following representation can be pasted in most Sudoku programs:

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

| 4      125   6    | 25   39    359 | 12358  7    12589 |

| 89     258   3589 | 257  379   1   | 4      6    259   |

| 179    1257  359  | 6    8     4   | 1235   239  1259  |

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

| 2      3     589  | 57   1679  569 | 178    4    167   |

| 16789  1567  589  | 3    4     569 | 1278   28   1267  |

| 167    1467  147  | 8    167   2   | 9      5    3     |

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

| 678    9     14   | 14   36    368 | 23578  238  2578  |

| 3      48    2    | 49   5     7   | 6      1    89    |

| 5      1678  17   | 19   2     368 | 378    389  4     |

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

Representation of the step:

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

|  4      125    6    |  25    39     359 | 12358    7    12589 |

|  89     258    3589 |  257   379    1   | 4        6    259   |

|  179    1257   359  |  6     8      4   | 1235     239  1259  |

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

|  2      3      589  |  57    1679   569 | 178      4    167   |

|  16789  1567   589  |  3     4      569 | 1278    B28   1267  |

|  167    1467   147  |  8     167    2   | 9        5    3     |

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

| A678    9      14   |  14   A36    A368 | 2-3578  B238  2578  |

|  3      48     2    |  49    5      7   | 6        1    89    |

|  5      1678  C17   | C19    2      368 | 378     B389  4     |

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



Almost Locked Set XY-Wing: A=r7c156 {3678}, B=r579c8 {2389}, C=r9c34 {179}, X,Y=7,9, Z=3 => r7c7<>3