Sudoku
Play unlimited sudoku with hints and four difficulties.
Play now →Sliding Puzzle
The classic 15-puzzle, digitized: slide tiles into the empty space and order them 1 through 15. Every shuffle is solvable, your move count is the score, and tiles glow green when they sit in the right place.
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Moves
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Best moves
Slide tiles into the empty space. Order them 1 → 15!
How to play
- The board is shuffled — one space is empty.
- Click any tile next to the empty space to slide it in.
- Reorder the board so tiles read 1 → 15 left to right, top to bottom.
- Correctly placed tiles glow green. Solve it in as few moves as you can.
Frequently asked questions
What is the sliding puzzle?
It is the classic 15-puzzle: a 4×4 tray holding 15 numbered tiles and one empty space. You slide a tile next to the space into it, one move at a time, until the numbers run 1 to 15 in order.
Is every shuffle solvable?
Yes. Every board here is generated by making legal slides from the solved state, so a solution always exists — a path of legal moves literally leads back to it. Historically, half of all random arrangements of the original 15-puzzle were impossible, which caused a famous craze in the 1880s.
What is a good number of moves?
A 100-move scramble typically has an optimal solution in the 40–80 range. Finishing under about 120 moves is strong play. Your move count is the score — lower is better.
Is there a solving strategy?
The standard method is to build the board in snake order: place tiles 1–4 across the top row, 5–8 across the next, and so on, keeping already-placed rows untouched. The last two rows need a cyclic rotation trick — easiest to learn by watching the bottom-left corner.
Does a wrong move ruin the puzzle?
Never — every move is reversible, and there is no time limit. Treat wasted moves as tuition: the move counter is your scoreboard, and undoing by hand costs exactly what it would in the optimal path.