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 HARD I hope you will enjoy my book. I would also really appreciate it if you could write a review. Thank you. Best regards, Andrii Pitenko