●Puzzle Research Institute, Sudoku● The cover is bent, and there are some creases inside. I noticed this after purchasing. The sides of the book are sun-faded. Please consider this before purchasing. ・Difficult Problems Edition ・Advanced Edition Size: B6 size? Price: 693 yen x 2 books Please refrain from purchasing if you are concerned, as this item has been stored at home. *No price reduction is offered.