In classic sudoku, the objective is to fill a 9×9 grid with digits so that each column, each row, and each of the nine 3×3 subgrids that compose the grid contain all of the digits from 1 to 9.
The puzzle setter provides a partially completed grid, which for a well-posed puzzle has a single solution.

Features:
- Four different difficulties for 9x9
- Statistics: track your progress for each difficulty level
- Two grid styles (classic or colorfully)
- Automatically save progress (if you leave a game with numbers unfinished, it will be saved)
- Highlighting of a row, column, and box related to the selected cell
- Hints for beginners
- Explaining mistakes
- The possibility to place notes
- Counting each number left in the grid