15 Puzzle

How to play the 15 puzzle

1. Slide tiles into the empty space until the numbers read 1 to 15 in order, gap at the bottom right. Tap a tile next to the gap — or any tile in the gap's row or column, and the whole run slides over in one move.
2. Arrow keys and swipes work too: the tile moves in the direction you press.
3. Solve the top row first, then the second; finish the last two rows together, column by column from the left. The endgame is a 2×3 dance worth learning.
4. The clock starts on your first move. Fewer moves and faster times both count — your best per size is saved on this device.
5. Painted yourself into a corner? Restart replays the exact same scramble; New shuffle deals another.

A little background

The fifteen puzzle is the oldest sliding puzzle there is — a postmaster named Noyes Chapman built the first one around 1874, and by 1880 it was a full-blown craze on two continents. Puzzle showman Sam Loyd later claimed he invented it and offered $1,000 to anyone who could solve a board with just the 14 and 15 swapped. He never paid, and never had to: mathematicians had already proven that exactly half of all arrangements are impossible, that one included. Every shuffle here is checked by that same parity rule, so the board you get is always the solvable half.

This version keeps the feel of the pocket toy — ivory tiles clacking in a little red frame — in three sizes: 3×3 for small hands, the classic 4×4, and a patient 5×5. And it adds the thing the plastic one never could: a live race. Two phones get the identical scramble, a mini copy of your rival's board sits beside yours, and the first to click every tile home takes the round. Free, no ads, no account — solo play works offline once loaded.