Masaki Hoshiko

Hard Sudoku Puzzle Book #18

Hard Sudoku Puzzle Book #7

The Sudoku Book For Hard Thinkers #21

The Sudoku Book For Hard Thinkers #7

Hard Sudoku Puzzle Book #5

Hard Sudoku Puzzle Book #19

Hard Sudoku Puzzle Book #9

Hard Sudoku A Day Collection #7

Hard Sudoku A Day Collection #8

Hard Sudoku A Day Collection #3

The Sudoku Book For Hard Thinkers #13

Hard Sudoku A Day Collection #6

Hard Sudoku A Day Collection #4

Hard Sudoku Puzzle Book #4

Hard Sudoku Puzzle Book #15

Hard Sudoku A Day Collection #11

The Sudoku Book For Hard Thinkers #20

Hard Sudoku A Day Collection #9

Brain Training Sudoku Puzzles #13

The Sudoku Book For Hard Thinkers #18

Brain Training Sudoku Puzzles #16

Hard Sudoku A Day Collection #5

Hard Sudoku Puzzle Book #16

Hard Sudoku Puzzle Book #17