How to Play Samurai Sudoku
Five overlapping 9×9 grids sharing corner boxes
The Rules
Standard Sudoku rules apply: fill every row, column, and 3×3 box with the digits 1–9, each appearing exactly once.
Samurai Sudoku consists of five interlocking 9×9 grids arranged in an X shape — one central grid and four corner grids, all sharing a 3×3 box where they overlap. Each of the five sub-grids must independently satisfy standard Sudoku rules. Solving one sub-grid often provides clues that unlock another. The complete puzzle spans a 21×21 grid.
For where this puzzle came from, how it compares with related variants and a strategy summary, see our Samurai Sudoku variant overview.
At a Glance
How to Solve Samurai Sudoku
Common Questions
What is Samurai Sudoku? ▾
Samurai Sudoku is a variant consisting of five overlapping 9×9 Sudoku grids arranged on a 21×21 board. One grid occupies the centre, and four grids are placed at the corners with their inner 3×3 boxes overlapping the centre grid's corner boxes. All five grids must be solved simultaneously.
How do the overlapping boxes work? ▾
Each of the four outer grids shares one 3×3 box with the centre grid. Any digit placed in a shared box satisfies the constraint for both grids simultaneously. This means information flows between grids through the shared boxes — solving one grid's corner often directly advances the centre grid.
Do all five grids have standard Sudoku rules? ▾
Yes. Each of the five 9×9 grids individually follows all standard Sudoku rules: every row, column, and 3×3 box within that grid must contain 1–9 exactly once. The only interaction between grids is through the shared corner boxes.
Is Samurai Sudoku harder than regular Sudoku? ▾
Samurai puzzles take significantly longer than single-grid Sudoku simply due to scale — you're solving five grids. Individual difficulty can range from easy to expert. The cross-grid interactions through shared boxes add a satisfying extra layer that single-grid Sudoku doesn't offer.
What is the best approach to Samurai Sudoku? ▾
Work on all five grids simultaneously rather than trying to complete one before moving to another. When you get stuck on one grid, the shared boxes often provide a breakthrough from a neighbouring grid. Scan all five grids for hidden singles after every placement in any shared box.
How long does Samurai Sudoku take to solve? ▾
Easy puzzles take 25–45 minutes. Medium puzzles run 45–90 minutes. Hard and expert puzzles can take 2–4 hours. The time is primarily driven by scale — five full grids — rather than by individual deduction difficulty.