SFC Sudoku SenseiScreenshot
Sudoku is an extremely fun logic-based number puzzle. You need to fill a 9x9 grid so that each column row, and all of the 9 3x3 boxes contains the digits from 1 to 9. Usually you are provided a partially completed grid to begin with. It was originally created by an American named Howard Garns in 1979 and then under the name "Number Place". It became popular in Japan in 1986, after it was published by Nikoli and given the name Sudoku.