200 excellent puzzles 9x9 at the level of Very Hard. Perfect for Advanced and Intermediate players. All riddles have only 1 solution. 2 puzzles per page.The font size is correct, you will not have to strain your eyes when solving puzzles. High quality paper and print (all puzzles read well, easy to write with pen and pencil without worry of bleed-through). Center Dot is a variant of sudoku, where central cells of each region form an extra region. This region must contain digits 1 through 9.