Samurai Sudoku
Five overlapping 9×9 grids sharing corner boxes
Easy
Samurai Sudoku Easy
Medium
Samurai Sudoku Medium
Hard
Samurai Sudoku Hard
Expert
Samurai Sudoku Expert
What is Samurai Sudoku?
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.
At a Glance
| Constraint type | 5 Overlapping Grids |
| Typical givens | ~30 per sub-grid |
| Difficulty rating | ★★★★★ 5/5 |
| Avg. solve time — Easy | 45 min |
| Avg. solve time — Medium | 90 min |
| Avg. solve time — Hard | 150 min |
| Avg. solve time — Expert | 240 min |
How to Solve Samurai Sudoku
| Technique | What it does | Level |
|---|---|---|
| Sub-Grid Independence | Each of the five 9×9 sub-grids satisfies standard Sudoku rules independently. Solve each one using all standard techniques. | Beginner |
| Overlap Box Exploitation | The four corner boxes where sub-grids meet are shared between two grids. Any digit placed in a shared box eliminates that digit from two sub-grids at once. | Intermediate |
| Cross-Grid Cascade | Completing a corner box in the central grid forces values in the corresponding corner grid's box, which may cascade further through that grid. | Intermediate |
| Shared Box Forcing | When a shared box is nearly complete, use both sub-grids' row and column constraints to force the remaining digits. | Advanced |
| Global Number Counting | Across all five sub-grids, each digit 1–9 appears 5×9=45 times total. This global count can confirm placement decisions near the end. | Advanced |
Average Solve Times
Easy
45 min
Medium
90 min
Hard
150 min
Expert
240 min
Frequently Asked Questions
How many sub-grids are there?
Five: one central grid and four corner grids, all arranged in an X or plus shape.
How many cells are in a Samurai puzzle?
369 valid cells total — five 9×9 grids with four shared 3×3 corner boxes subtracted.