Sudoku Kyo free sudoku game

Sponsored Links

TOP > Techniques > Aligned Pair Exclusion

Solving Techniques 19
Aligned Pair Exclusion

Please have a look below. We have the blue cells [4,8][2,8], which are strongly related to the pink cells [2,4][2,5,8].

The possible combinations of the two pink cells are.
[2][2]
[2][5]
[2][8]
[4][2]
[4][5]
[4][8]
The combination of [2][2] is impossible.

The [2][8] combination can’t be used because A9’s candidate is [2,8].

The [4,8] combination can’t be used because B1’s candidate is [4,8]. Hence we have,
[2][2]
[2][5]
[2][8]
[4][2]
[4][5]
[4][8]
and [8] can’t be entered in C1.

As seen above, the Aligned Pair Exclusion technique, considers all possible combinations between two cells to narrow down the candidates.

Aligned Pair Exclusion 2

Here is another sample. Lets examine the pink cells in the diagram above. The combinations are
[1][3]
[1][4]
[1][9]
[3][3]
[3][4]
[3][9]
[8][3]
[8][4]
[8][9]

If the pink cells are [1][3], then the blue cells in the same box will be [7][7], which won’t work out.

If the pink cells are [1][4], then the blue cell in E3’s candidate will be [1,4], which won’t work out.

If the pink cels are [3][8], the candidates in the blue cell, I3, will be [3,8], which won’t work out.
[1][3]
[1][4]
[1][9]
[3][3]
[3][4]
[3][9]
[8][3]
[8][4]
[8][9]
Hence, a [3] can’t be entered to the right of the pink boxes.

Sponsored Links

Aligned Pair Exclusion 3

Here is another sample. Lets examine the pink cells in the diagram above. The combinations are:
[4][3]
[4][7]
[5][3]
[5][7]
[7][3]
[7][7]

If the pink cells are [4][7], then the same box’s blue cells will become [1][1], which won’t work out.

If the pink cells are [5][7], then the blue cell in C8’s candidates will be [5,7] which won’t work out.
[4][3]
[4][7]
[5][3]
[5][7]
[7][3]
[7][7]
Therefore, a [7] can’t be entered below the pink cells, so a [3] is confirmed here.

Aligned Pair Exclusion 4

Here is another sample. Lets examine the pink cells in the diagram above. The combinations are:
[1][1]
[1][6]
[1][8]
[9][1]
[9][6]
[9][8]

If the pink cells are [1][8], the candidates in the blue cell, A1, will be [1,8], which won’t work out.

If the pink cells are [9][8], the candidates in the blue cell, F2, will be [8,9], which won’t work out.
[1][1]
[1][6]
[1][8]
[9][1]
[9][6]
[9][8]
Hence, an [8] can’t be entered below the pink cells.

Aligned Pair Exclusion 5

Here is another sample. Lets examine the pink cells in the diagram above. The combinations are:
[1][4]
[1][5]
[1][7]
[2][4]
[2][5]
[2][7]
[7][4]
[7][5]
[7][7]

If the pink cells are [1][4], the candidates for the blue cell, I2, will be [1,4], which won’t work out.

If the pink cells are [1][5], the candidates for the blue cell, H2, will be [1,5], which won’t work out.

If the pink cells are [1][7], the candidates in both the blue cells A3 and C3 will be [9], which won’t work out.
[1][4]
[1][5]
[1][7]
[2][4]
[2][5]
[2][7]
[7][4]
[7][5]
[7][7]
Hence, a [1] can’t be entered to the left of the pink cells.

reference: sudokuwiki.org

Names of cells in Sudoku

A1A2A3A4A5A6A7A8A9
B1B2B3B4B5B6B7B8B9
C1C2C3C4C5C6C7C8C9
D1D2D3D4D5D6D7D8D9
E1E2E3E4E5E6E7E8E9
F1F2F3F4F5F6F7F8F9
G1G2G3G4G5G6G7G8G9
H1H2H3H4H5H6H7H8H9
I1I2I3I4I5I6I7I8I9

Sponsored Links

Sudoku Kyoto(Number Place)Free Puzzle Game
TOP