The objective is to fill a 9x9 grid with digits so that each column, each row, and each of the nine 3x3 sub-grids that compose the grid contains all of the digits from 1 to 9.

FEATURES:
- four different difficulties
- hundreds of puzzles for each difficulty
- auto-save your progress for each puzzle
- unlimited undo/redo
- auto-fill drafts
- clean interface and smooth controls
- phones and tablets support