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

Solving Technique Example

Original sudoku:

.1....5.8...4.3....567.........2..8.4.....3.22..376..19.8...254.....7...........3

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

:0800:9:+71+4.+6.5+38+8..4+53..+7+3567+1+8+4+2+9....2+4.8+54.....3.22+8+5376+9+419+78+6+3+1254.....7..+6........3::942 943 954 955 956:

The following representation can be pasted in most Sudoku programs:

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

| 7    1    4    | 29    6    29  | 5    3    8 |

| 8    29   29   | 4     5    3   | 16   16   7 |

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

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

| 16   369  1379 | 19    2    4   | 67   8    5 |

| 4    69   179  | 1589  89   59  | 3    67   2 |

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

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

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

| 15   234  123  | 2589  489  7   | 18   19   6 |

| 156  246  12   | 2589  489  259 | 178  179  3 |

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

Representation of the step:

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

|  7     1     4     |  29     6    29  | 5    3    8 |

|  8     29    29    |  4      5    3   | 16   16   7 |

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

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

| *16    36-9  137-9 | *19     2    4   | 67   8    5 |

|  4    *69    179   |  158-9  8-9  5-9 | 3    67   2 |

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

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

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

|  15    234   123   |  2589   489  7   | 18   19   6 |

|  156   246   12    |  2589   489  259 | 178  179  3 |

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



XY-Wing: 1/6/9 in r4c14,r5c2 => r4c23,r5c456<>9