Expert Samurai Sudoku
Score
-
Mistakes
0/3
Time
00:00
9
5
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Expert · Samurai · 5 sub-grids0%
How to play Samurai Sudoku
Five overlapping 9×9 Sudoku grids. Each sub-grid must independently satisfy standard Sudoku rules (1–9 in each row, column, and box). Where two sub-grids share a 3×3 corner box, that box must satisfy both grids simultaneously. Solve sub-grids with the most clues first, then use shared boxes to unlock others.
About Samurai Sudoku
Difficulty
★★★★★
5/5
Constraint Type
5 Overlapping Grids
Typical Givens
~30 per sub-grid
Avg. Solve (Medium)
90 min
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.
Solving Techniques
| Technique | Description | 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 Time by Difficulty
Easy
45 min
Medium
90 min
Hard
150 min
Expert
240 min