Sliding Block Puzzle

The Sliding Puzzle is the classic puzzle format where tiles slide on a grid to rearrange them into a target pattern. The most famous variant is the 15 Puzzle (4×4 with numbered tiles), but sliding puzzles come in many configurations. Whether picture-based or number-based, sliding puzzles test spatial reasoning, planning, and patience.

How to play

• A grid of tiles with one empty space.
• Click on a tile adjacent to the empty space to slide it, or use the arrow keys.
• Continue sliding tiles to arrange them into the target pattern.
• Minimum solution length depends on starting state.
• Choose 3×3 up to 6×6, and switch between numbered and coloured gradient tiles. Moves and time are tracked, and your fewest-moves solve for each size is saved in this browser.

Beginner strategy

• Solve the top row first, then work down row by row, and finish the last two rows column by column.
• Use corner technique for end of rows.
• Don’t break solved rows.
• Use blank as your manipulator. Move the blank around.
• Take your time. 100-200 moves is normal for a human solve on 4×4.

Intermediate strategy

• Layer-by-layer solving. Each layer locks in.
• The “twin” trick. For the last 2 tiles of a row, line them up together just below their spots, then rotate them in as a pair.
• Column-by-column endgame. Last rows solve column-by-column.
• Pattern memorization. Learn the few short move sequences for placing row-end and column-end tiles.
• Speed solving. Top speedsolvers finish a 4×4 in well under 10 seconds.

Common mistakes

• Random sliding. Without method.
• Breaking solved rows. Loses progress.
• Counting moves while solving. Counts distract.
• Restarting often. Most mistakes recoverable.

FAQ

• Q: Are all positions solvable? A: For 15 Puzzle, exactly half are solvable. This version shuffles using legal slides, so every puzzle is solvable.
• Q: Best technique? A: Layer-by-layer solving — top row, middle rows, bottom row.
• Q: How long does it take? A: Any 4×4 position can be solved in 80 moves or fewer, but 100-200 moves is typical for a human. A minute or two for skilled casual solvers.
• Q: Difference from 15 Puzzle? A: Sliding puzzle is the general format; 15 Puzzle is the specific 4×4 numbered variant.

For other puzzle games, try 15 Puzzle, Tower of Hanoi, Lights Out, or Maze.