Sudoku Jigsaw (also known as "Irregular", "Nonomino" or "Geometric Sudoku") is a logic-based, combinatorial number-placement puzzle. Jigsaw Sudokus are very similar to regular Sudoku puzzles.Regular 9x9 Sudoku that row and column rules apply, but instead of a 3x3 grid they are nine Jigsaw shapes. The puzzle books series contain: - 500 Normal Puzzles- Handy 6 x 9 inch Book Layout- 6 Puzzles per Page- Ideal for Beginners The book is for those who like logic and math problems. Decide, developing and improving.