200 excellent puzzle 9x9 at the level of Very Hard.For Advanced Players. All riddles have only 1 solution. 2 puzzles per page. Argyle Sudoku is based on the original Sudoku grid, with the same rules and numbers-1 to 9(no number may appear twice in any row or column and rectangles of 3x3).Argyle Sudoku contains additional diagonals; every marked diagonal line contains each digit not more than once.Sudoku puzzles will help you to distract from everyday thoughts and relax. Regular puzzle solving trains your brain, develops memory and logical thinking. Also increases the skill of concentration.