ref: 8f5ab25e8696f51f2be8a6743edc2de68c9451d6
dir: /sys/games/lib/sudoku/boards/easy-2005-03-29.su/
.6..9.... ..74..... 9.4...7.8 .76.8...3 1.57.46.9 3...6.57. 8.3...9.2 .....13.. ....2..4. 268397451 537418296 914256738 476589123 125734689 389162574 843675912 792841365 651923847