Samurai Sudoku: 500 Sudoku Puzzles Overlapping Into 100 Samurai Style: Hard Level (Paperback) (ISBN-13: 9798668546992)

As one of the sudoku variants, Samurai Sudoku consists of five overlapping sudoku grids, one in the center and the other 4 overlapping each corner grid of the central one.

The standard sudoku rules apply to each 9 x 9 grid, which means the numbers must be placed correctly for all the five puzzle squares. The goal is to fill in the empty cells, one number in each, so that each column, row, and region (3 x 3 subgrids in the 9 x 9 grid) contains the numbers 1 through 9