How to play
Click any tile in the same row or column as the empty space to slide it (and any tiles between) into the gap. Arrow keys move the tile next to the gap. Arrange the tiles in order from 1 in the top-left, reading left to right, with the empty space last. Tiles turn gold when they are in their correct position.
How to solve it
- Solve the top row first, one tile at a time. Place the last two tiles of the row together using a small rotation.
- Solve the left column the same way. Now you have a smaller puzzle.
- Repeat until a 2×3 or 3×3 area remains, then cycle the last tiles around the gap.
- Never break a finished row to fix a later tile – move tiles through the unsolved area instead.
FAQ
Is every shuffle solvable?
Yes. Boards are shuffled by making random legal moves from the solved state, so a solution always exists. (Half of all random arrangements would be impossible.)
Why is it called the 15 puzzle?
The classic 4×4 version has 15 tiles. It became a worldwide craze in 1880.