What is a slide puzzle?
The slide puzzle is one of the oldest and most satisfying puzzles around, and its simple gap-and-tiles idea has hooked players for well over a century.
How it works
On a slide puzzle, one square is always empty. You can only move a tile that sits next to that gap, sliding it into the space. Do that enough times in the right order and the scrambled numbers fall back into sequence, from 1 up to the top count.
A quick history
The puzzle appeared around 1874 thanks to Noyes Chapman, and by 1880 it had become a worldwide craze. The showman Sam Loyd famously promoted it and offered a prize for an unsolvable version, which helped cement its fame. Our guide to solving the 15 puzzle covers the modern method.
Sizes and difficulty
A 3x3 board with eight tiles is a friendly warm-up, while 4x4 and 5x5 boards ramp up the planning required. The bigger the grid, the more moves you juggle, which is why the slide puzzle grows with you as you improve.
Related questions
How do you solve a 15 puzzle?
Solve a 15 puzzle in layers. Finish the top row first, then the left column, which shrinks the puzzle to a smaller grid. Repeat until only a 2x2 block remains, which you rotate into place. Handling the last two tiles of each row with a small rotation is the key trick.
Is every slide puzzle solvable?
Not every possible arrangement is solvable. A rule called parity means about half of all random tile layouts can never be sorted, no matter how you move. The good news is that Puzzle.now only ever generates scrambles that are guaranteed solvable, so your board always has an answer.
Which puzzle is best for beginners?
For a gentle start, try the classic Slide Puzzle, Memory Match, or an easy Word Search. Their rules take seconds to learn and give quick, satisfying wins. Once you are comfortable, 2048 and nonograms add more depth without feeling overwhelming.