Nikoli's Pencil Puzzle

Nikoli's Pencil Puzzle is a set of four different logic puzzle categories: Hashi, a bridge-connection puzzle; Shikaku, an area-filling puzzle; Akari, a hidden-space puzzle similar to Minesweeper; and Sudoku, a numbers puzzle. Each of the four categories has between 70 and 300 puzzles separated into Intro, Easy, Normal, and Hard, for a total of 600 puzzles. Attribution: User Summary