The New Sudoku Players' Forum

[apatt]

Given:

*-----------*
|5..|...|.6.|
|...|...|..2|
|...|639|.7.|
|---+---+---|
|1.6|...|9..|
|..3|785|4..|
|..4|...|8.3|
|---+---+---|
|.3.|842|...|
|9..|...|...|
|.2.|...|..1|
*-----------*


Got as far as:

*-----------*
|5..|21.|369|
|369|...|1.2|
|.12|639|57.|
|---+---+---|
|186|.2.|957|
|293|785|416|
|754|...|823|
|---+---+---|
|631|842|795|
|9..|...|2..|
|.2.|...|6.1|
*-----------*

then stuck...
Thanks!

[dazzle0076]

547,218,269
369,574,182
812,639,574

186,423,957
293,785,416
754,196,823

631,842,795
975,361,248
428,957,631

[Scott H]

"Simple coloring" of 4s quickly shows r8c9 can't be 4, hence r8c9 = 8. The puzzle solves easily from there. The reasoning: r8c9 = 4 forces r9c1 = 4, and these force r3c1=8 and r3c9=8, a contradiction (two 8s in row 3). So r8c9 <> 4.