ref: b143811a53bf25824e74b7e6e6c2ee7af8c7a954
dir: /sys/games/lib/sudoku/boards/easy-2005-01-30.su/
5.2..9.4. 3...4.... .7.5.3.9. 7.6.98... ..4...1.. ...17.8.4 .5.9.1.3. ....8...6 .2.3..7.8 562819347 391746285 478523691 716498523 284635179 935172864 857961432 143287956 629354718