ref: 8188b4f4f0e07b6669e6ae3c6c1099af917eaab4
dir: /sys/games/lib/sudoku/boards/hard-2005-03-26.su/
..8..457. ......... .1..726.3 .....8.1. .62.1.84. .8.5..... 5.169..3. ......... .498..7.. 238164579 796385124 415972683 957248316 362719845 184536297 521697438 873451962 649823751