The New Sudoku Players' Forum

[Gee]

I just can't seem to get the hang of multi-coloring. In the puzzle below I am working with "1"s, I colored r1c2 orange.....r2c1 pink....r9c1 orange....r9c2 pink. Then I colored r4c5 green and r4c8 blue. My thinking was that since r1c8 could be "seen" by r1c2 and r4c8 I could exclude the "!" in r1c8. By the same logic I thought that I could exclude the "!" in r2c8 because it was "seen" by r2c1 and r4c8. Could someone please help me to see the error of my ways. Thank you for your help.


*--------------------------------------------------------------------*
| 4 168 2 | 3 9 5 | 7 168 18 |
| 179 5 79 | 6 2 8 | 4 139 139 |
| 689 3689 3689 | 1 7 4 | 568 2 589 |
|----------------------+----------------------+----------------------|
| 5 2 78 | 4 18 3 | 9 178 6 |
| 689 689 4 | 7 168 2 | 58 1358 1358 |
| 3 678 1 | 5 68 9 | 2 78 4 |
|----------------------+----------------------+----------------------|
| 6789 4 689 | 2 3 1 | 568 56789 5789 |
| 279 379 39 | 8 5 6 | 1 4 279 |
| 1268 168 5 | 9 4 7 | 3 68 28 |
*--------------------------------------------------------------------*

[underquark]

Multicolouring here only tells you that r1c8 can't be orange and it can't be blue. It could be green, it could be pink, pink could be the same as green etc. Only when the two colour sets overlap or conflict elsewhere can you infer or exclude a cell.