Easy 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

New to Cube Sudoku? Two 9x9 grids overlap at a shared corner box — start there, as it receives constraints from both grids simultaneously.

Score
0
Mistakes
0/3
Time
00:00
Grid A
5
3
1
9
7
6
2
1
9
7
7
2
4
6
8
8
7
4
1
9
4
8
2
1
3
8
6
4
9
4
3
7
2
1
5
9
2
7
9
3
5
6
9
6
9
2
5
4
1
6
3
2
1
3
8
2
9
7
3
7
1
8
4
5
7
1
2
6
4
6
7
5
Grid A Shared Grid B
Grid B
Try Medium Cube Sudoku →
Easy · 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 (Easy)
15 min

Solving Techniques for Easy 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

Ready to go deeper? Try Medium Cube / 3D Sudoku to unlock Intermediate techniques.

Techniques to Master at Easy

  • Last Free Cell technique — Two grids mean 18 rows, 18 columns, and 17 distinct boxes to scan — and the shared corner box closes units in both grids whenever it gains a digit.
  • Last Remaining Cell technique — Digits in the shared box answer to both grids' rows and columns, halving their legal cells — when either grid stalls, the overlap is where placements remain findable.

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 →

Related Variants

Samurai Sudoku

The full-scale version of multi-grid solving — five grids instead of two, all trading digits through shared boxes.

Hyper Sudoku

Overlap logic inside a single grid: four windows that share cells with the standard boxes the way your grids share a corner.

Jigsaw Sudoku

A single-grid geometry challenge — irregular regions demand the same spatial flexibility as twin-grid bookkeeping.

Frequently Asked Questions — Easy Cube Sudoku

What is Cube Sudoku (3D Sudoku)?
Cube Sudoku — also called 3D Sudoku — uses two overlapping 9x9 Sudoku grids displayed as a 15x15 layout. Grid A covers rows 1-9 and columns 1-9. Grid B covers rows 7-15 and columns 7-15. The 3x3 region in the bottom-right corner of Grid A (rows 7-9, cols 7-9) is shared with the top-left corner of Grid B. Both grids must independently satisfy standard Sudoku rules.
How does the shared corner region work in Cube Sudoku?
The shared 3x3 box sits at the intersection of Grid A and Grid B. It counts as a box in Grid A and also as a box in Grid B. Any digit you place there must be valid in both grids simultaneously — it must not conflict with any row, column, or box in Grid A and must also not conflict with any row, column, or box in Grid B. This double membership makes the shared region the most constrained area of the puzzle.
How is Cube Sudoku different from regular Sudoku?
Regular Sudoku has 81 cells and one set of row, column, and box rules. Cube Sudoku has 153 cells (two 9x9 grids minus the 27 shared cells counted once) and two independent sets of Sudoku rules linked at one corner. You must solve both grids in parallel, using information from each grid to constrain the other through the shared region.
Where should I start in an easy Cube Sudoku?
Start with the shared 3x3 box. Because it belongs to both grids, it receives information from more rows and columns than any other box. Cells in the shared box that are already given, or that can be deduced from their position in either grid, often unlock placements in both Grid A and Grid B simultaneously.
How do I tell which grid a cell belongs to in Cube Sudoku?
The blue-tinted cells belong to Grid A only. The green-tinted cells belong to Grid B only. The overlap cells (lighter tint) belong to both grids. The color coding on the board makes it immediately clear which uniqueness rules apply to each cell. Always check both grid memberships before placing a digit in the overlap.

More questions? See the full Cube Sudoku guide.