Difficult Sudoku Twelve Logic Puzzles (Vol 1)
Chapter 42: Two Difficult (DiffLev 10-13) Productively Puzzles (numbers 163-164)
- Step-by-step instructions for solving Puzzle 163, (84/144) Diff: 10/99.9964.4434
- Step-by-step instructions for solving Puzzle 164, (95/144) Diff: 13/9.9247.8768.8984