Sudoku Activity Level 1-5 - There is hardly anybody who does not know about Sudoku. Our intention behind creating this series is to cater to the whole family. Rather than fighting over the same book of 1000 puzzles, this series values sharing. Levels 1-3 are designed as an introduction for new players (Typically Age 6-10, but new players irrespective of age can use) and Levels 4-5 are created for experts. We start level 1 with a 4X4 grid and we move to 9X9 by the time we reach Levels 4-5.