Shikaku Solver
Enter your puzzle below — grid size, then the numbered clues — and get the unique solution instantly. Works for any Shikaku, including newspaper puzzles and LinkedIn Patches grids.
Grid size
How to use the solver
- Choose your grid size, or type a custom width and height (up to 25×25).
- Tap each numbered cell and enter its clue — the area of the rectangle it belongs to.
- Press Solve. The unique solution appears as coloured rectangles on the grid.
How the solver works
The solver runs an exact-cover search over every rectangle each clue could form, then fills the grid cell by cell until one clue's rectangle covers each empty cell — and it keeps searching for a second solution, so it can verify the puzzle has exactly one. Prefer to solve it yourself? Read the techniques.
When a puzzle has no solution
Two things can go wrong: the clues admit no valid tiling ("No valid solution"), or they admit more than one ("Multiple solutions", which means it is not a proper Shikaku). By far the most common cause is a mistyped clue — a single wrong number makes a solvable board look impossible, so re-check your entries first.