🔢 Sliding Puzzle
Slide tiles into numerical order from 1 to the end. One space is empty. Click any tile next to the empty space to slide it in. Arrow keys also work.
Tap a tile to slide it into the empty space. Arrow keys move the empty space.
About This Game
Sliding tile puzzles train sequential spatial planning, and they punish greed harder than almost any other puzzle, because putting one tile right usually requires temporarily disturbing others. Accepting short term disorder to reach long term order is the entire skill.
There is real mathematics underneath. Exactly half of all possible tile arrangements are solvable, determined by a parity property of the scramble, which is why a properly shuffled puzzle is always winnable while randomly placed tiles may not be.
Solving a 3 by 3 in under 60 moves is competent. A 4 by 4 solved at all without help is a genuine achievement.
The tip most people miss: solve the last two tiles of each row together, never one at a time. Place the final tile of a row on its own and the second to last becomes impossible to insert without breaking what you just finished. Experienced solvers set both into a specific corner formation and rotate them in as a pair. Not knowing this is why most people complete two rows and then loop forever.
How to Play the Sliding Puzzle
Click any tile adjacent to the empty space to slide it into the gap. The goal is to arrange all tiles in numerical order from 1 upward, with the empty space in the bottom-right corner. Arrow keys move the empty space in that direction, pulling the adjacent tile with it.
Is It Always Solvable?
Not every random arrangement of tiles can be solved. Exactly half of all possible arrangements are unsolvable due to parity constraints. This version checks solvability before presenting any puzzle, so every game you get is guaranteed to have a solution.
Strategy
Solve the top rows first, then the left column, working down and right. Avoid moving tiles out of already-solved positions. The last 2x2 area in the bottom-right requires a specific rotation sequence to complete without disturbing the rest of the board.
Frequently Asked Questions
What is the minimum number of moves to solve?
Is every puzzle solvable?
Can I use keyboard controls?
What is a good score?
Try These Next
How Do You Play Sliding Puzzle?
Numbered tiles sit in a grid with one empty space. Click or tap a tile adjacent to the gap to slide it in. Rearrange the tiles into numerical order to solve the puzzle. Only tiles next to the empty square can move, which is the constraint that makes the puzzle hard despite its simple goal.
Roughly half of all random arrangements of a standard sliding puzzle are unsolvable, a property of the tile parity, so a shuffled board is always generated from a solved one here.
What Are the Cognitive Benefits of Spatial Puzzles?
Sliding puzzles train spatial working memory and sequential planning: you must hold a target arrangement in mind while executing moves that temporarily make the board look worse.
Planning practice of this kind is discussed in research indexed by the National Library of Medicine.
The honest caveat is that gains are largely specific to the skill you practise. Research on cognitive training transfer found that transfer to unrelated tasks is real but usually modest, so treat these as focused practice rather than general brain training.
Tips to Improve Your Sliding Puzzle Score
Solve the top row first and then leave it alone, working down row by row. For the final two rows, work in columns instead. Learn the three move cycle that rotates three tiles without disturbing the rest, since almost all endgame work uses it. Accept that fixing the last row requires temporarily breaking it, which is the step most people resist.
Are all shuffled arrangements solvable?
No. About half of all random arrangements of a standard sliding puzzle cannot be solved, a property of tile parity. Boards here are generated by shuffling from a solved state, so every puzzle you are given is solvable.