ref: 08c1622b0d8de92c2650d7b0338d9abf20985827
dir: /sys/games/lib/sudoku/boards/easy-2005-02-08.su/
9.4..68.. ....9.... 256..3.1. ....8..62 ..15794.. 73..6.... .4.2..679 ....3.... ..96..3.1 914726853 387195246 256843917 495381762 621579438 738462195 543218679 162937584 879654321