This print is modelled after the Japanese number game using colors for mathematical symbols. Sudoku, also known as Number Place or Nanpure, is a logic-based placement puzzle. The aim of the puzzle is to enter the digits 1 through 9 in each cell of a 9×9 grid made up of 3×3 subgrids (called "regions") so that each row, column, and region contains exactly one instance of each digit. A set of clues, or "givens", constrain the puzzle such that there is only one way to correctly fill in the remainder. Completed sudoku puzzles are a type of Latin square, with the additional constraint on the contents of individual regions. Leonhard Euler is sometimes cited as the source of the puzzle based on his work with Latin squares. -- Source of annotation: Marvin or Ruth Sackner.