HoDoKu Solving Technique Index: Example for "ALS Chain"

Solving Technique Example

Original sudoku:

....3.......2...577.....81.1.9..5....6...4.3.....82.....87....44......8..37..15..

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

:9003:69:..+1.3+7......2+1+8.577.....81.1.9+3+65....6..+74.3.....82.....87....44.....+78..37+8+415..:212 412 914 932 533 934 939 277 677 977 582 984 289 689 989:611 911 912 927:

The following representation can be pasted in most Sudoku programs:

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

| 25689  589   1    | 456  3    7   | 2469  2469  269   |

| 369    49    346  | 2    1    8   | 3469  5     7     |

| 7      245   2346 | 456  59   69  | 8     1     236   |

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

| 1      2478  9    | 3    6    5   | 24    247   28    |

| 258    6     25   | 19   7    4   | 129   3     12589 |

| 35     457   345  | 19   8    2   | 1469  4679  1569  |

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

| 2569   1259  8    | 7    259  369 | 13    269   4     |

| 4      129   256  | 56   259  369 | 7     8     13    |

| 269    3     7    | 8    4    1   | 5     269   269   |

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

Representation of the step:

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

|  25-68-9   58-9   1    | A456  3    7   | A2469   A2469  A269   |

| D369      D49    D346  |  2    1    8   |  346-9   5      7     |

|  7         245   D2346 |  456  59   69  |  8       1      236   |

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

|  1         2478   9    |  3    6    5   |  24      247    28    |

|  258       6     C25   |  19   7    4   |  129     3      12589 |

|  35        457    345  |  19   8    2   |  1469    4679   1569  |

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

|  2569      1259   8    |  7    259  369 |  13      269    4     |

|  4         129   C256  | B56   259  369 |  7       8      13    |

|  269       3      7    |  8    4    1   |  5       269    269   |

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



Almost Locked Set Chain: 69- r1c4789 {24569} -5- r8c4 {56} -6- r58c3 {256} -2- r2c123,r3c3 {23469} -69 => r1c1<>6, r1c12,r2c7<>9