How to play

The tiles are numbered and there is one empty space. Slide a tile into the gap by tapping or clicking it; if the tile is in the same row or column as the gap, the whole line of tiles between them moves together. You can also use the arrow keys, which move the tile on the opposite side of the gap into it. Arrange the numbers in order, 1 first, with the gap in the bottom right corner.

Pick a 3 × 3 board (8 tiles), the classic 4 × 4 (the “15 puzzle”) or a hard 5 × 5. Every shuffle is made by sliding tiles from the solved position, so every puzzle can be solved. Your best move count for each size is saved in this browser.

Tips

Solve the top row first, then the next row, and leave the last two rows for the end. Place the last two tiles of a row together: put the second one directly below its spot, then rotate both into place. Be patient; with practice the 4 × 4 takes under a hundred moves.

Is my progress saved? Only your size and your best scores, in this browser. Nothing is sent anywhere.