You are about to access our book library "BIG BOOK SUDOKU -very hard- 250 logical puzzle + bonus 250 classic Killer Sudoku: 50 Patchwork doku 12 x 12 + 50 KenKenDoku 9 x 9 + 50 Hidoku-doku 12 ... puzzles - 12 x 12 (PITSTOP Puzzle Bonus) full version" .