A samurai sudoku is five classic 9×9 sudokus arranged like an X: a middle grid shares each of its corner boxes with one of four outer grids. The shared boxes link the puzzles, so you cannot solve the grids one by one in isolation. This samurai sudoku solver treats the whole 369-cell puzzle as one, proves that it has a single solution, and walks you through it.
How to enter the puzzle
- Tap any cell of the five grids and type its digit. Arrow keys jump across the gaps between grids.
- Or paste the puzzle as text: either five grids of 81 characters in the order top-left, top-right, middle, bottom-left, bottom-right (405 characters), or the whole 21 by 21 square row by row (441 characters, any character in the gaps).
- Press Solve for the full answer, or Next hint to work through it.
On a phone the grid is wider than the screen; swipe sideways inside the grid area to reach the right-hand grids.
How it is solved
Each of the five grids has its own rows, columns and boxes, and a cell in a shared box belongs to two grids at once, so it must fit the rows and columns of both. The exact search handles all 369 cells together. The hints use the same techniques as the sudoku solver, and each one names the grid it happens in, for example “row 7 of the middle grid”. Cell names count rows and columns across the whole 21 by 21 square, so R7C7 is the top-left cell of the middle grid.
The shared corners are where the grids help each other: a digit placed in the middle grid's corner box also counts in the outer grid, which often unlocks a stuck outer grid. Watch for hints that highlight a box of one grid and a row of another.
Tips
- Check the shared boxes carefully when typing: a clue there appears once on the page but belongs to two grids.
- If the solver finds two solutions, a clue is missing; the cells that differ are highlighted so you can compare them with your source.
For one large grid instead of five linked ones, the 16x16 sudoku solver works the same way with sixteen symbols.
To play a full samurai, try samurai sudoku online: five linked grids with saved progress and a daily puzzle.
Solver tested . Found a problem? Tell us.
Questions
What is a samurai sudoku?
Five 9×9 sudokus that overlap: the middle grid shares each corner box with one outer grid. Every grid follows the normal rules, and the shared boxes count for both grids.
How many cells does a samurai sudoku have?
369: five grids of 81 cells is 405, minus the four shared boxes of 9 cells that are counted twice.
Can I solve the five grids separately?
Usually not. Each grid on its own normally has many solutions; only the shared boxes make the whole puzzle unique.
What text format does the samurai solver accept?
Five grids of 81 characters (405 in total) in the order top-left, top-right, middle, bottom-left, bottom-right, or the full 21 by 21 square as 441 characters.