Sudoku Adventure on Latin Squares, first posed by Leonhard Euler in 1783, and recently developed into a game known as Number Place or Sudoku, popular in the U.S. and Japan. This popular 81-square puzzle game is found frequently in newspapers and puzzle books and has become quite an obsession among puzzle enthusiasts.

Sudoku (Japanese: ??, sudoku), sometimes spelled Su Doku, is a logic-based placement puzzle, also known as Number Place in the United States. The aim of the canonical puzzle is to enter a numerical digit (excepting 0) in each cell of a 9?9 grid made up of 3?3 subgrids (called "regions"), starting with various digits given in some cells (the "givens"). Each row, column, and region must contain only one instance of each numeral. Completing the puzzle requires patience and logical ability. Although first published in 1979, Sudoku initially caught on in Japan in 1986 and attained international popularity in 2005.