8x8 Sliding Puzzle Solver

The largest supported square

An 8x8 sliding puzzle contains 63 tiles and one blank, using all 64 cells. The difficulty is not just remembering more labels. A tile near one corner may need a long corridor to reach the opposite side, and every completed boundary removes part of that corridor. The board rewards a method that maintains an organized working region while progressively reducing it.

This is the largest square supported by the sliding puzzle solver. It is a single-blank sliding puzzle, even if a game presents it as a photo, a pattern, or a set of numbered tiles. Boards with walls, multiple gaps, or pieces that rotate have different rules and cannot be represented faithfully by this preset.

Enter all 64 cells explicitly

Use Edit start → Type numbers to copy eight entries from each row, left to right and top to bottom. Labels run from 1 to 63 and the blank is 0 or _. Spaces and commas both separate values. The input checks the total count and detects repeated, missing, or invalid labels, but you should still compare the displayed arrangement with your source: a complete set can be placed in the wrong cells.

For picture boards, upload the completed image with Photo before arranging the pieces. Number each piece by its location in the completed picture. On a crowded board, a tiny feature near an edge may distinguish two otherwise similar pieces. Edit start lets you swap two cells to correct them. If the finished picture uses a different blank location, configure it with More → Edit goal instead of assuming the bottom-right cell.

Move-count scale without a false promise

The board's distance sum offers a useful starting estimate. For each numbered tile, count how many rows and columns separate it from its target, then add those distances. Leave out the blank. If 63 tiles average five grid steps from their targets, the total is 315; any route for that example needs at least 315 single-tile moves. This is a deliberately stated example, not a measured typical length for an 8x8 scramble.

The supplied route can contain more slides because arranging one piece may require moving several others away and back again. Large boards can therefore produce long move lists, while an almost finished 8x8 board may need only a handful of single-tile moves. Each item in the replay moves one tile into the blank. Moving a whole row with one gesture still represents multiple individual slides in the count.

Plan around borders and bottlenecks

One common opening is a scattered top row with its corner pieces far apart. Bring the required pieces into the active area before closing that row. Another is a complete row combined with a disordered first column; preserve the row while leaving room to position the column's final pair. If several outer borders are already correct, identify the remaining square and work within it rather than restarting the entire board.

A narrow end region is a different kind of challenge. A pair in the wrong local order may need a cycle through neighboring positions, and locking one of them prematurely can obstruct the other. Follow the replay through those temporary movements. Counting currently correct tiles is a useful progress signal, but it cannot decide whether a particular next slide is productive.

A constructive route for a very large state space

For 8x8, the solver does not run a full-board exhaustive search. It restores an outer row and column, marks settled cells as locked, and continues inside the remaining region. Each placement search tracks a tile or a tile pair with the blank while allowing other unsettled pieces to circulate. The blank is excluded from locked cells during the later placements.

The row and column endings are handled as pairs, avoiding a stranded last piece. Once only a 3x3 region remains, the solver translates its labels, finishes it using a distance table, and maps the moves back to the 8x8 board. It removes adjacent immediate reversals from the combined route. This produces a fast answer that you can inspect and execute, without a claim that every other full-board route has been compared.

Check parity before committing to playback

The standard 8x8 target has the blank in the bottom-right corner. Read the numbered pieces in row order, omit the blank, and count reversed pairs. Add the blank's row counted upward from the bottom, with the bottom row equal to one. The sum must be odd for that standard target. The tool also supports custom targets and checks reachability against the actual goal entered.

If the board is reported as impossible, first compare the goal and input with the external puzzle. A mistaken pair can create a correct-looking but unreachable arrangement. Fix it changes two neighboring numbered tiles; apply it when you want a corrected board, not when you must preserve the exact external position. After Solve, pause or slow playback and use the named tile plus its arrow to reproduce the route without confusing tile direction with blank direction.