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

Solving Technique Example

Original sudoku:

3.4.2..8...6.......5..7.3.....68..2.....34....6.15.7...1.........9....6...8217..5

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

:0701:7:3.4+52..8...6.+9.....5..7.3.....68+9.2+3...+734....6+315+27...1.+9+6......9.+4..6.+6.8217..5::742:

The following representation can be pasted in most Sudoku programs:

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

| 3      79   4   | 5    2  16  | 169    8     1679  |

| 1278   278  6   | 348  9  138 | 1245   1457  1247  |

| 1289   5    12  | 48   7  168 | 3      149   12469 |

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

| 1457   47   157 | 6    8  9   | 145    2     3     |

| 12589  289  125 | 7    3  4   | 15689  159   1689  |

| 489    6    3   | 1    5  2   | 7      49    489   |

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

| 2457   1    257 | 9    6  358 | 248    347   2478  |

| 257    237  9   | 38   4  358 | 128    6     1278  |

| 6      34   8   | 2    1  7   | 49     349   5     |

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

Representation of the step:

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

| 3      *79    4   | 5    2  16  | 169     8     *1679  |

| 1278    278   6   | 348  9  138 | 1245   *1457   1247  |

| 1289    5     12  | 48   7  168 | 3       149    12469 |

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

| 1457    4-7  *157 | 6    8  9   | 145     2      3     |

| 12589   289   125 | 7    3  4   | 15689   159    1689  |

| 489     6     3   | 1    5  2   | 7       49     489   |

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

| 2457    1    *257 | 9    6  358 | 248    *347    2478  |

| 257     237   9   | 38   4  358 | 128     6      1278  |

| 6       34    8   | 2    1  7   | 49      349    5     |

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



X-Chain: 7 r1c2 =7= r1c9 -7- r2c8 =7= r7c8 -7- r7c3 =7= r4c3 => r4c2<>7