Goal: Fill every empty square with the correct number from 1 to 9.

Each row must contain the numbers 1–9 exactly once.
Each column must contain the numbers 1–9 exactly once.
Each 3×3 box must contain the numbers 1–9 exactly once.

Click an empty square, then press a number below the board. Use CLEAR to erase your selected square.

Check marks incorrect entries.
Solve fills the selected square with its correct value.
New lets you choose a difficulty.