Slide numbered tiles into order. 3 by 3, 4 by 4 or 5 by 5, a daily board, a picture mode, moves and time with your best per size, and a hint for the 3 by 3.
A sliding puzzle is a square grid of numbered tiles with one empty square, the gap, and you solve it by sliding tiles into the gap until the numbers run in order from 1, left to right and top to bottom, with the gap in the bottom-right corner. A 3 by 3 board has 8 tiles, a 4 by 4 board has 15 (the classic 15 puzzle) and a 5 by 5 board has 24. Only a tile in the gap's row or column can move. Tap the tile next to the gap to slide it in, or tap a tile further along the same row or column to slide it and every tile between it and the gap at once. Each tile that moves counts as one move, so sliding three tiles at once adds 3. Take the board 1 2 3, 4 5 6, gap 7 8: tap the 8 and both the 7 and the 8 slide left, which solves the board in 2 moves. The clock starts with your first move and stops when the board is solved.
On a touch screen, tap a tile or swipe on the board. On a keyboard, press an arrow key: the key names the direction the tile travels, so Left slides the tile on the right of the gap one square left, into the gap. Up slides the tile below the gap up, Right slides the tile on the left of the gap right, and Down slides the tile above it down. An arrow does nothing when no tile is on that side of the gap. The arrow keys work while the board is on screen and leave scrolling alone when you have scrolled away from it. Picture mode draws a gradient picture across the board and cuts it into tiles, each with a small number, so you can solve by the picture. Nothing is downloaded: the pictures are drawn by your browser. The Daily 4 by 4 board is made from the date on your device, so everyone with the same date gets the same board. Your board is saved as you play, and the last 12 boards are kept.
Only half of all possible arrangements of a sliding puzzle can be solved, so a board made by shuffling the tiles at random would be unsolvable half the time. This tool shuffles from a seed and then checks the arrangement with the parity rule. Count the inversions: pairs of tiles, ignoring the gap, where the larger number comes first in reading order. On a 3 by 3 or 5 by 5 board an arrangement is solvable when the inversion count is even. On a 4 by 4 board it is solvable when the inversion count plus the gap's row, counted from the bottom with the bottom row as 1, is odd. If an arrangement fails the check, two tiles swap places, which changes the parity once and makes it solvable. For example, 2 1 3, 4 5 6, 7 8 gap has one inversion and cannot be solved, and the classic 15 puzzle with only the 14 and the 15 swapped fails the 4 by 4 rule. A 3 by 3 board has 181,440 solvable arrangements and a 4 by 4 board has 10,461,394,944,000. Boards that are already solved or very close to solved are skipped.
Show hint works differently by size. On the 3 by 3 board it searches for a shortest solution with IDA*, a depth-first search that deepens its limit step by step and uses the Manhattan distance to cut off hopeless paths. It then highlights the first tile to slide and tells you how many moves a shortest finish needs. The search stops after 400,000 positions; if it ever runs out it says so instead of guessing. The position 8 6 7, 2 5 4, 3 gap 1 needs 31 moves at best. On 4 by 4 and 5 by 5 boards no search is run, because the number of positions is far too large for a quick answer. Hint shows the Manhattan distance instead: for each tile, the rows plus columns it is from its home square, added up. It is 0 only when the board is solved, and the bar beside it shows how far it has fallen since the start. A game where you used a move hint still counts as solved but does not set your best.
A common method is to solve the top row, then the next row, working down until two rows are left, and then to finish those two rows one column at a time. Keep the tiles you have placed still and move the gap around them. A tap on a tile further along the gap's row or column moves several tiles in one go, so look for a tap that puts one tile in place without disturbing the rest. Your best moves and best time for each size are saved in this browser, and so is the daily streak. The time pauses while the tab is hidden. A game where you used a move hint does not change your best. There is no sound, no undo and no move limit, and nothing is sent anywhere.
Yes, every board here is. Half of all arrangements cannot be solved, so each board is checked with the parity rule (even inversions on a 3 by 3 or 5 by 5 board, a row-based test on 4 by 4) and repaired with one swap if it fails.
Tap a tile that is in the gap's row or column but not next to the gap. It and every tile between it and the gap slide one square towards the gap. Each tile that moves counts as one move, so sliding 3 tiles adds 3 to your moves.
The arrow key is the direction the tile travels. Left slides the tile on the right of the gap one square left. Right slides the tile on the left of the gap right. Up slides the tile below the gap up, and Down slides the tile above the gap down.
It shows the Manhattan distance: for each tile, the rows plus columns it is from its home square, added up. It does not name a move, because only the 3 by 3 board is searched. On 3 by 3 it highlights a first tile and gives the length of a shortest finish.
The Daily board is 4 by 4 and is made from the date on your device, such as 2026-10-15, plus the game name. Everyone with the same date gets the same board. It counts once a day toward your daily streak, and the date is checked again when you return to the tab.
No. The game runs in your browser and nothing is uploaded. Your board in progress, your options, your best moves and your best times are saved in this browser's storage and stay on this device. The page counts visits with Google Analytics, never your boards or moves.