How to play a slide puzzle

Move into the gap.

A tile can move if it is immediately above, below, left or right of the empty space. Click or tap that tile to slide it into the gap.

Tiles cannot move diagonally, jump over each other, wrap around the edge or swap places directly. One slide counts as one move.

Here, sliding 8 into the gap finishes the board.

Start with 3 × 3.

The 3 × 3 board has eight tiles, so it is also called the 8-puzzle. Its finished rows are 1–2–3, then 4–5–6, then 7–8–gap.

The 4 × 4 board has fifteen tiles and is known as the 15-puzzle. Read across each row: 1–4, then 5–8, then 9–12, then 13–14–15–gap.

Open “See the goal” next to the board if you want a small visual reference. There is no countdown or target score to beat.

Think about where the space goes.

Before a slide, look at the tile you want to move and where the gap needs to be. Sometimes you must move a number away from its final position to make room for another.

On 3 × 3, try arranging the first row, then work on the remaining tiles. Move the gap around a small square to see how the numbers cycle. Avoid repeatedly undoing the same slide unless you are deliberately changing direction.

If you lose your place, Undo takes back one move. You can also use a hint without losing the board.

Two sizes, two kinds of hint.

On 3 × 3, Hint marks a tile that begins a shortest solution from the current position. That does not make your whole attempt the shortest if you have already taken extra moves.

On 4 × 4, Route hint follows a known legal route back to the goal. It can retrace your earlier moves and does not promise the shortest solution. If you keep making the suggested slide, the route reaches a completed board.

A hint highlights the tile; it does not move it for you. Choosing a different move is fine—the next hint uses your new position.

Every starting board is made by legally sliding away from a finished board. Those slides can be reversed, so every generated puzzle is solvable.

Daily and practice boards.

Daily gives everyone the same board for a size and UTC date. New 3 × 3 and 4 × 4 boards arrive at 00:00 UTC. If the date changes while you are playing, you can finish the open board or choose “Play today’s board.” Your saved daily stays available when you reopen. Choose Play today to replace it; an unfinished board asks for confirmation.

Practice creates a fresh puzzle whenever you choose “New practice puzzle.” The game asks before replacing an attempt in progress. Switching between sizes or modes keeps each board’s progress in this browser, when saving is available.

Restart restores the same starting arrangement and resets that attempt’s moves and hints. Undo also works after a win.

Keyboard, mouse or touch.

Click or tap a tile beside the gap. For keyboard play, press Tab to focus the board, then use the Arrow keys to move the empty space in that direction. For example, ↑ moves the gap upward by sliding the tile above it down.

You can also Tab to a movable numbered tile and press Enter or Space to slide it. The gap stops at the board edge. Each tile has a label with its number, row, column and whether it can move. The game announces each move and the gap’s new position. Reduced-motion preferences remove the sliding animation.

Keep your place.

Progress is saved in this browser on this device. No account is needed. Clearing site data, private browsing or blocked storage can remove or prevent saves.

If a saved puzzle cannot be read, you can continue without saving. The previous record is kept until you choose to reset it. Read the privacy information.