Medium Samurai Sudoku

Five overlapping 9×9 grids share corner boxes. Solve all five simultaneously — each shared box belongs to two grids at once.

Easy Medium Hard Expert

Stepping up from Easy Samurai Sudoku? Shared overlap boxes act as bridges — completing one sub-grid propagates digits into its neighbors.

Score
-
Mistakes
0/3
Time
00:00
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Try Hard Samurai Sudoku →
Medium · Samurai Sudoku · 5 sub-grids 0%
How to play Samurai Sudoku
Five overlapping 9x9 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 3x3 corner box, that box must satisfy both grids simultaneously. Solve sub-grids with the most clues first, then use shared boxes to unlock others.
How to Play Samurai Sudoku →

What is Samurai Sudoku?

Difficulty
★★★★★
5/5
Constraint Type
5 Overlapping Grids
Typical Givens
~30 per sub-grid
Avg. Solve (Medium)
90 min

Solving Techniques for Medium Level

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

Master these, then take on Hard Samurai Sudoku to learn Advanced techniques.

Techniques to Master at Medium

  • Hidden Singles technique — After any placement in a shared corner box, re-scan the rows and columns of BOTH owning grids — hidden singles triggered in the neighbour grid are the easiest ones to miss.
  • Obvious Pairs technique — A pair in a shared box eliminates into two grids simultaneously — pairs found in the four overlap boxes are worth double those found anywhere else on the board.

Average Solve Time by Difficulty

Easy
45 min
Medium
90 min
Hard
150 min
Expert
240 min
Want a full walkthrough of rules, strategies, and solving steps? How to Play Samurai Sudoku →

Related Variants

Jigsaw Sudoku

A different geometry challenge in one grid — region shapes that snake instead of grids that overlap.

Chaos Construction

For solvers who enjoyed scale, chaos offers depth: deduce the hidden region borders while solving.

Hyper Sudoku

Overlapping regions condensed into a single 9×9 — four windows that share cells with the standard boxes.

Frequently Asked Questions — Medium Samurai Sudoku

What is the best strategy for medium Samurai Sudoku?
Work through each sub-grid systematically, starting with the most constrained. When you complete or nearly complete a shared overlap box, immediately check how those digits propagate into the adjacent sub-grid — this often yields several free placements in the neighboring grid.
How do I use shared boxes strategically in medium Samurai Sudoku?
Shared boxes act as bridges. If you know six of the nine digits in a shared box from one sub-grid's constraints, the remaining three slots are limited. Combined with what the other sub-grid tells you about rows/columns passing through that box, you can often pin down the remaining digits.
Can I solve each Samurai sub-grid independently?
Not fully — the shared boxes mean you cannot treat sub-grids as completely separate puzzles. However, sub-grids without shared-box progress can often be advanced significantly using only their own internal clues. You alternate between grids as each unlocks the others through the shared boxes.
How long does medium Samurai Sudoku take?
Medium Samurai Sudoku typically takes 30–60 minutes. The larger board means more time overall, but medium puzzles have enough given digits that at least one or two sub-grids yield quickly and drive progress across the rest.
Do all five Samurai sub-grids need to be equally solved before the puzzle is complete?
Yes — all five sub-grids must be completely and correctly filled. The puzzle is finished only when every non-gap cell on the full 21x21 board holds a valid digit.

More questions? See the full Samurai Sudoku guide.