What Is an 8 Puzzle? Rules, Goal & Tips
An 8 puzzle is a 3x3 sliding game with eight numbered tiles and one blank. Slide adjacent tiles into the blank to place 1 through 8 in order. Learn the rules and try a move.
An 8 puzzle is a sliding-tile puzzle on a 3x3 board. Eight squares carry the numbers 1 to 8; the ninth square is empty. You move one tile at a time into that empty space, aiming to arrange the numbers in order. The name refers to the eight numbered tiles, not to the number of moves needed to win.
You can play it with a small physical board or in a browser. The rules are the same in both versions: you cannot lift a tile, jump over another tile, or move diagonally. Every move changes where the blank sits, so planning its route matters as much as tracking the numbers.
What Does a Solved 8 Puzzle Look Like?
On this site, the goal is 1, 2, 3 across the top row; 4, 5, 6 across the middle; and 7, 8, blank across the bottom. The blank finishes in the lower-right corner. Some books or classroom exercises use another target arrangement, so check the pictured goal before you begin.
For a one-move example, imagine the bottom row is 7, blank, 8 while the first two rows are already correct. Slide tile 8 left into the blank. The bottom row becomes 7, 8, blank, and the puzzle is solved. Tile 8 moved; the empty space moved right.
How Do You Play?
Find the empty square first. A numbered tile can slide into it only if the tile touches it above, below, left, or right. Then find the next useful legal move. You are not required to solve the board in eight moves; a scrambled board can take many more.
In our online game, click or tap an adjacent tile to move it. On a desktop, the arrow keys also work. The timer starts with your first move, and the game counts the moves you make. A physical sliding toy uses the same rules, but you push the pieces with your hand.
- Move only one tile into the blank per turn.
- Do not move diagonally or swap two numbered tiles directly.
- Finish with 1 through 8 in order and the blank at the lower right.
Can Every Starting Board Be Solved?
No. If someone places the eight tiles in an arbitrary order, the resulting board may be impossible to reach from the goal by legal slides. For example, starting from the solved board and swapping only tiles 7 and 8 produces an unsolvable arrangement. Sliding alone cannot repair that isolated swap.
The 8-puzzle game on this site creates a new board by making legal moves from a solved board. Reversing those moves would return it to the goal, so every generated board is solvable. If you are using a physical toy or entering a board into a solver, do not assume the same about a manually arranged position.
A Simple Beginner Strategy
Start by looking for a path that brings 1, 2, and 3 toward the top row. Before each slide, ask where the blank will end up and whether that lets you move the next needed tile. Try to protect a completed row, but do not treat it as untouchable: a temporary setup move can be useful if you restore it later.
Once the upper row is in place, work on the left side and use the remaining open squares to cycle tiles into position. A common mistake is to chase one numbered tile without considering the blank's route. Another is to expect the last two misplaced tiles to be swapped directly; only a sequence of legal slides can change their order.
What Is an 8 Puzzle Solver?
A solver searches for a sequence of legal moves from a given board to its goal. It can also identify an impossible starting arrangement. In computer science, the 8 puzzle is a familiar example for explaining search algorithms such as A*, which compare possible board states and choose a path to the solution.
If you use a solver to learn, inspect just the next few moves before trying again yourself. Notice how each move positions the blank for the next tile. Copying an entire move list will finish the board, but it teaches you less about why the sequence works.
8 Puzzle vs. 15 Puzzle
The 15 puzzle follows the same sliding rule but uses a 4x4 board with 15 numbered tiles and one blank. The 8 puzzle's smaller board makes it a comfortable place to learn how to route the blank and preserve progress. Once those ideas feel natural, try the larger board; the extra spaces give you more pieces to manage.
Ready to see the rules in action? Open the 8-puzzle game above, find the blank, and make one adjacent slide. You will immediately see how moving a tile changes your options for the next turn.
A worked example
A fixed teaching position, separate from your current game.
| 1 | 2 | 3 |
| 4 | 5 | 6 |
| · | 7 | 8 |
| 1 | 2 | 3 |
| 4 | 5 | 6 |
| 7 | 8 | · |
The upper rows are already complete. Tap 7, then 8, to move each tile into the neighboring blank. The board is solved without disturbing those rows. A tempting diagonal tile cannot move: only a shared edge makes a legal move in this version.
Frequently asked questions
What is an 8 puzzle in simple terms?
It is a 3x3 sliding puzzle with eight numbered tiles and one empty space. Move adjacent tiles into the blank until the numbers reach the goal order.
Why is it called the 8 puzzle?
It has eight numbered tiles. The board has nine squares because one square is left blank for sliding; the name does not describe the number of moves.
Can you move an 8 puzzle tile diagonally?
No. Only a tile directly above, below, left, or right of the blank can slide into it.
Is every 8 puzzle arrangement solvable?
No. Some manually arranged boards cannot be solved with legal moves. This site's game shuffles by making legal moves from a solved board, so its generated boards are solvable.