- Code: Select all
*-----------*
|5.3|2.4|...|
|8..|3..|1..|
|74.|.9.|..3|
|---+---+---|
|...|...|4.7|
|1..|6.3|..8|
|9.4|...|...|
|---+---+---|
|6..|.3.|.89|
|..9|..7|..4|
|...|5.9|3.1|
*-----------*
*-----------*
|513|284|..6|
|89.|37.|14.|
|74.|19.|8.3|
|---+---+---|
|.6.|9..|4.7|
|1..|643|..8|
|9.4|7..|6..|
|---+---+---|
|6.1|432|.89|
|..9|817|.64|
|4..|569|3.1|
*-----------*
*--------------------------------------------------*
| 5 1 3 | 2 8 4 | 79 79 6 |
| 8 9 26 | 3 7 56 | 1 4 25 |
| 7 4 26 | 1 9 56 | 8 25 3 |
|----------------+----------------+----------------|
| 23B 6 58 | 9 25G 18 | 4 13 7 |
| 1 27- 57 | 6 4 3 | 29K 259 8 |
| 9 238* 4 | 7 25B 18 | 6 13 25- |
|----------------+----------------+----------------|
| 6 57 1 | 4 3 2 | 57 8 9 |
| 23 235 9 | 8 1 7 | 25M 6 4 |
| 4 278M 78 | 5 6 9 | 3 27K 1 |
*--------------------------------------------------*
I put the filter on candidate 2 and started colouring.
I later saw that there were easier eliminations which would do the same thing. But I saw this nonetheless.
B,G,K, and M are the four colours that I have used. B and G form one conjugate pair while K and M form another.
- are the cells from which 2 can be eliminated.
That would have been obvious if I had remembered to colour r8c1 with G.
I would have also been able to eliminate the 2 in r6c2 by use of the naked pair of 2 and 5 on row 6.
In the method I used, I used saw that the absence of 2 in the * cell would have allowed me to colour the - cells with G and thus eliminate all Gs since the Gs would see both K and M. As things stood, I could at least eliminate the - cells because of one piece of observation.
If 2 is in the * cell, the - cells can be eliminated.
If 2 is not in the * cell, the - cells can be eliminated.
This may afterall have been a useless post. I restarted this puzzle and tried to set up a position where the move I used would be necessary to solve the puzzle. I was able to avoid the naked pair, but I couldn't establish another 2 in column 1.
Here is a virtual example though.
- Code: Select all
*--------------------------------------------------*
| 5 1 38 | 2 38 4 | 79 79 6 |
| 238 9 286 | 38 7 56 | 1 4 25 |
| 7 4 26 | 1 9 56 | 38 25 38 |
|----------------+----------------+----------------|
| 23B 6 58 | 9 25G 18 | 4 13 7 |
| 1 27- 57 | 6 4 38 | 29K 259 38 |
| 9 238* 4 | 7 125B 18 | 6 13 25- |
|----------------+----------------+----------------|
| 6 57 1 | 4 38 2 | 57 38 9 |
| 23 235 9 | 38 1 7 | 25M 6 4 |
| 4 278M 78 | 5 6 9 | 38 27K 1 |
*--------------------------------------------------*
This is the position at which my method works even though you might want to eliminate the 2 from r2c1 before you apply this method. However, I noticed that simple sudoku says this puzzle has 316 solutions. I have not used any uniqueness conditions and was able to solve this puzzle. So, can this have more than one solution? Or is this a BUG in the program?
This example is slightly better because even though one doesn't need to apply my technique here if he filters 3 or 8 first. Yet, if 2 is filtered first, you can see the link between two unconnected conjugate sets.
