Click a square, then type 1–9. Backspace clears. Arrow keys move.
THE EXACT RULES
Fill the 9×9 grid so every row, every column and every 3×3 box holds
1–9 once each. The givens in grey are clues and
cannot be changed. A digit that already appears in the same
row, column or box is REJECTED — the square keeps its old
value and no mistake is counted. A digit that is legal on the board but disagrees with the
unique solution is a MISTAKE. 3 mistakes
= game over. WIN = all 81 squares filled and every one of
them correct. Puzzles are carved from a freshly generated full grid and are only accepted
if the number of solutions is exactly one — Easy removes 32 cells,
Medium 40, Hard 48, so every puzzle you are shown has exactly one answer.
Slot satellites into orbits within a move budget. Each manifest has one solution.
Rotate pipe tiles around bedrock to connect source to sink.
Fill the grid from the number clues to reveal a hidden picture.
Push every crate onto its target. You can push, never pull.
Thread the gaps. Your best score is saved on this device.
Five in a row against an AI that scores every candidate move.
Two piles, optimal play. The AI always leaves you a losing position.
Descending waves, destructible shields and a rising score.
