Find sudoku lessons, classes, and instructors at HeyKiki and learn to to master sudoku. Up until 2005, the strategic game was limited to the residents of Japan - the country where it originates from. The concept is simple: a square box of a certain width and length contains a single number in each row or column. Your job: make sure the same single number does not appear up, down or across. That's actually where the name come from: sudoku means single number in Japanese.