Medium Cube/3D Sudoku

A classic 9×9 grid folded onto the faces of a cube. Rows and columns wrap across face boundaries in three dimensions.

Easy Medium Hard Expert

Cube Sudoku at medium difficulty. Deductions in one grid propagate into the other through the shared region — solve both grids in parallel.

Score
0
Mistakes
0/3
Time
00:00
Grid A
1
9
4
9
2
8
6
5
8
9
4
8
7
1
5
2
6
7
4
6
8
6
9
7
8
4
8
7
6
4
3
8
2
5
4
3
4
5
9
6
3
5
8
4
9
6
6
3
8
6
1
3
5
6
4
4
8
9
5
3
6
2
Grid A Shared Grid B
Grid B
Try Hard →
Medium · Cube/3D · 2 grids (153 cells)0%
How to play Cube/3D Sudoku
Two 9×9 Sudoku grids overlap at a shared 3×3 corner box. Grid A (blue tint) covers rows 1–9, columns 1–9. Grid B (green tint) covers rows 7–15, columns 7–15. The shared box (rows 7–9, cols 7–9) satisfies both grids. Each grid must independently satisfy standard Sudoku rules.
How to Play Cube / 3D Sudoku →

What is Cube / 3D Sudoku?

Difficulty
★★★★☆
4/5
Constraint Type
Twin Grids
Typical Givens
~30 per grid
Avg. Solve (Medium)
32 min

Solving Techniques for Medium Level

Technique Description Level
Shared Box Exploitation The overlapping 3×3 box satisfies both grids. Digits placed here eliminate from rows and columns in both Grid A and Grid B simultaneously. Beginner
Grid A/B Isolation Outside the shared box, each grid operates independently. Apply standard 9×9 Sudoku logic to each grid in turn. Intermediate
Cross-Grid Cascade Completing the shared box often cascades through the adjacent rows and columns of both grids, rapidly resolving nearby cells. Intermediate

Master these, then take on Hard Cube / 3D Sudoku to learn Advanced techniques.

Average Solve Time by Difficulty

Easy
15 min
Medium
32 min
Hard
60 min
Expert
95 min
Want a full walkthrough of rules, strategies, and solving steps? How to Play Cube / 3D Sudoku →

Frequently Asked Questions — Medium Cube Sudoku

What techniques work for medium Cube Sudoku?
Medium Cube Sudoku requires treating both grids as linked systems. When you resolve a digit in Grid A's shared rows or columns, immediately check whether that elimination affects Grid B's candidates and vice versa. Apply hidden singles and naked pairs within each grid separately, then propagate constraints through the shared region to create cascades across both grids.
How does the shared region transmit information between grids in Cube Sudoku?
A digit placed in the shared box counts toward row and column constraints in both grids. For example, placing an 8 in the shared region removes 8 as a candidate from every cell in that row within Grid A and from every cell in the corresponding row within Grid B. This makes the shared region a bridge that lets deductions made in one grid propagate into the other.
Do I solve Grid A and Grid B independently in medium Cube Sudoku?
No. The grids must be solved in parallel. Treating them as independent puzzles is possible for cells that do not interact with the shared region, but as you progress, the shared corner creates dependencies that require alternating attention between both grids. The most efficient approach is to resolve the shared region first, then alternate between grids as new deductions arise.
How long does a medium Cube Sudoku take?
Most players finish a medium Cube Sudoku in 20 to 35 minutes. The 153-cell scope means more overall work than a standard puzzle, but the shared region provides a powerful deduction hub that often unlocks large sections of both grids simultaneously.
What happens if I place a wrong digit in the shared region?
A wrong digit in the shared region propagates errors into both grids because it violates rules in two independent Sudoku systems at once. Errors in the shared box tend to produce more cascading contradictions than errors elsewhere. Check shared-region placements against both grids before confirming.

More questions? See the full Cube Sudoku guide.