Variations on Advanced Sudoku Logic Puzzles (Vol 1)

Chapter 5: Four Difficult Sudoku-12 Puzzles (numbers 9-12)

• Step-by-step instructions for solving Puzzle 9, (84/144)   Diff: 13/9.9986.4335.3575
• Step-by-step instructions for solving Puzzle 10, (87/144)   Diff: 14/72.2459.5457.9994
• Step-by-step instructions for solving Puzzle 11, (88/144)   Diff: 14/99.5467.9726.8351
• Step-by-step instructions for solving Puzzle 12, (90/144)   Diff: 14/77.9993.3244.6887