## Multi-color Help

Advanced methods and approaches for solving Sudoku puzzles

### Multi-color Help

I got stuck with this multi-coloring during the solving this puzzle. I could solve the puzzle by other means. My question is this, is there a way to find which cells by logic. I could guess but that is not the answer.

I am working with "9's". I colored r1ci as amber and r1c5 as pink so I know either r1c1 or r1c5 is true.. I then colored r2c9 as blue, r3c7 as green, r5c7 as blue and r5c9 as green. From this arrangement is there a way using logic to determine which cell can be excluded.

Where might someone go to get more help with multi-coloring. Thanks.

Code: Select all
`*-----------------------------------------------------------------------------* | 379     137     5       | 2       169     36      | 8       367     4       | | 6       8       12349   | 1359    7       345     | 23      23      239     | | 3479    2347    23479   | 8       69      346     | 2379    1       5       | |-------------------------+-------------------------+-------------------------| | 1       9       2346    | 7       8       256     | 2345    23456   236     | | 57      257     8       | 4       3       1       | 2579    2567    2679    | | 3457    23457   23467   | 56      256     9       | 23457   8       1       | |-------------------------+-------------------------+-------------------------| | 8       6       13479   | 359     259     2357    | 123457  23457   237     | | 357     357     37      | 1356    4       23567   | 12357   9       8       | | 2       13457   3479    | 359     159     8       | 6       3457    37      | *-----------------------------------------------------------------------------*`
Gee

Posts: 50
Joined: 18 March 2007

### Re: Multi-color Help

Gee wrote:I got stuck with this multi-coloring during the solving this puzzle. I could solve the puzzle by other means. My question is this, is there a way to find which cells by logic. I could guess but that is not the answer.

I am working with "9's". I colored r1ci as amber and r1c5 as pink so I know either r1c1 or r1c5 is true.. I then colored r2c9 as blue, r3c7 as green, r5c7 as blue and r5c9 as green. From this arrangement is there a way using logic to determine which cell can be excluded.

Where might someone go to get more help with multi-coloring. Thanks.

Gee, you've probably already noticed that there are simpler methods available than multi-coloring at the point you gave, but here is a deduction using multi-coloring on 9's. All you need is to change your coloring a little:

Code: Select all
`*-----------------------------------------------------------------------------* | 379a    137     5       | 2       169     36      | 8       367     4       | | 6       8       12349-  | 1359    7       345     | 23      23      239b    | | 3479p   2347    23479   | 8       69      346     | 2379g   1       5       | |-------------------------+-------------------------+-------------------------| | 1       9       2346    | 7       8       256     | 2345    23456   236     | | 57      257     8       | 4       3       1       | 2579    2567    2679    | | 3457    23457   23467   | 56      256     9       | 23457   8       1       | |-------------------------+-------------------------+-------------------------| | 8       6       13479   | 359     259     2357    | 123457  23457   237     | | 357     357     37      | 1356    4       23567   | 12357   9       8       | | 2       13457   3479    | 359     159     8       | 6       3457    37      | *-----------------------------------------------------------------------------*`

If instead of coloring r1c5 with pink, you color r3c1 with pink, then pink sees green and hence any cell that sees both blue and amber cannot be a 9. In particular, r2c3<>9.

For places to find multi-coloring tutorials, I've always liked angusj's solving guide or for more in-depth analysis and advanced techniques, try Ruud's online solving guide.
re'born

Posts: 551
Joined: 31 May 2007