Sliding Puzzle

The 15-puzzle has been frustrating people since 1880. Tiles are shuffled, one square is empty, and you can only slide a tile into the gap — no lifting, no rotating.

It looks like a simple sorting task until you realise the last two rows require specific cycles to solve. Work the top rows first, keep the empty space where you need it, and never break a solved row to chase a quick fix.

Pick a 3×3, 4×4 or 5×5 board and see how few moves you need.

How to play Sliding Puzzle

• Click a tile next to the empty space to slide it over.
• Arrange the tiles in ascending order, left to right, top to bottom.
• The empty square ends in the bottom-right corner.
• Solve the top row first, then work downward.

Tips & strategy

The sliding puzzle looks like a sorting task, but the last two rows require deliberate cycles. Solve in layers and protect finished work.

• Solve the top row first, then the second row, working downward. Do not start in the middle.
• Keep the empty square inside the row you are currently solving; it is the only workspace you have.
• For the final two rows, solve them together as vertical columns rather than left to right.
• Learn the three-tile cycle: rotating three tiles around the blank reorders them without disturbing solved rows.
• Never break a finished row to chase a quick fix. If you must disturb it, restore it immediately.
• Count your moves. A clean 4×4 solve under 100 moves is a good benchmark.

Controls

Questions