Sudoku 9x9, separated by smaller squares of 3x3 cells. The entire playing field consists of 81 cells. It is required to fill empty cells with numbers from 1 to 9, each of the digits should appear only once in each row, column, and 3x3 square.An excellent book for free time pastime and mind training.Presented 141 pages. Format 8’’ x 10 ’’.4 Sudoku puzzle on the page. Conveniently positioned for better perception.401 unique puzzles. 100 EASY + 100 MEDIUM + 100 HARD + 101 VERY HARDI hope you will enjoy my book. I would also really appreciate it if you could write a review.Thank you.Best regards, Andrii Pitenko