A FAMILY OF SMALL MOVES
Sliding number
puzzles.
Sliding number puzzles turn one empty cell into a route. Choose a size, try a few moves, then open the full game that fits your pace.
Choose your board ↓TWO SIZES · ONE MECHANIC
Choose the space you want to think in.
WHAT MAKES A SLIDING PUZZLE?
A move opens
the next move.
Numbers stay on the board
Both boards have one empty cell. Slide a numbered tile from above, below, left or right into that cell. Read the solved numbers across rows from the top left; leave the gap in the bottom-right corner. There is no dragging a tile across several cells and no direct swap of two numbers.
Unlike a picture-sliding puzzle, every tile here tells you its intended position. Unlike a block-sliding puzzle, all pieces are one cell in size. Your constraint is the gap’s route, not the width of a particular piece.
Start with your finger or four keys
The short trial above switches between 3×3 and 4×4. It does not read or replace an unfinished game, and does not save a score. Use the matching full-game button for difficulty, hints, a clock and your own records. On a phone, tap a tile directly beside the gap. With a keyboard, focus the board and press the direction the numbered tile should travel. On the full game pages, the timer starts only after a legal slide. Pause, undo and restart give you room to inspect what changed.
Why our shuffles begin at the finish
Randomly rearranging labels can create an unreachable board. Legal slides from the goal preserve solvability. For 3×3, the inversion count must be even; for 4×4, inversions plus the gap’s row from the bottom must be odd. The different tests describe the same promise: every new board here has a route home.
A common strategy, scaled carefully
Build one edge and keep it still. The last two tiles of an edge need a shared route; forcing the last tile home on its own often traps its neighbor. Plan the gap’s return path before closing an edge. The worked 15 Puzzle strategy shows the two-slide finishing sequence.
Difficulty is a start, not a new rule
Each size has Easy, Medium and Hard shuffles. They change how far tiles begin from home and how thoroughly the board is mixed. Three-by-three Hard can still demand planning; a smaller board does not make every random move productive. Verified Hint routes are available on both sizes, with separate Assisted records.
Which kind of space do you enjoy?
Can I choose a different image for these tiles?
These boards use numbers and a fixed reading-order goal. They are not image-upload tools. A numbered goal makes it easier to see why a pair must be staged before an edge closes.
Does a short shuffle guarantee a short solution?
The shuffle gives a known route back, but revisiting positions can make a shorter route possible. We do not label a board with an optimal move count. Best scores compare your own completed attempts on this browser.