ref: 6397d1b59f175dc06428a6378ea9ac5548d94e59
dir: /sys/games/lib/sudoku/boards/easy-2005-02-06.su/
86.....9. ...6..8.7 2.3.....4 ....15.3. 3.78245.9 .5.39.... 9.....3.8 7.5..8... .8.....75 861457293 549632817 273189654 698715432 317824569 452396781 926571348 735948126 184263975