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Difficulty — every puzzle is solvable by logic alone, never guessing
Shape
Rules for the whole cube
Type

Standard keeps only the box layout from the rules above.

Generating…

Share / Import

Puzzle code: one line of text holding the whole puzzle (size, symbols, rules, givens, every clue, and the solution when known). Paste it anywhere; anyone can import it below.

Or a link that opens the puzzle directly:

Import: paste a puzzle code, share link or puzzle JSON, or open a file.

Settings

Privacy & storage

How to play LayerSudoku Rules & constraint gallery with pictures →

LayerSudoku is in beta. Found a bug, or have an idea? Tell us on Discord.

The cube

The puzzle is an N×N×N cube (9×9×9 by default; 4 to 12 are possible, with digits 1–N, 0–(N−1) or letters). Every line of N cells along X, Y or Z contains each symbol once. By default every box of every slice, in all three orientations, does too. Each slice is therefore an ordinary sudoku that also has to agree with the slices crossing it.

Navigating

  • Q W E — view XY / XZ / YZ slices through the cursor
  • [ ], PgUp PgDn or the mouse wheel — step to the previous / next slice (cursor follows)
  • ←↑↓→ — move in the slice (Shift/Ctrl to extend selection)
  • The depth strip beside the board shows the 9 cells along the depth axis through the cursor.
  • 3D view: drag to rotate, wheel to step slices, Ctrl+wheel (or pinch) to zoom, right-drag or Shift-drag to pan, click a cell to jump to it, double-click to face the active slice.
  • H — highlight the cursor's digit across the whole cube

Entering

  • 1–9 — enter in the current mode
  • Z digit, X corner, C centre, V colour, B pen, Space cycles
  • Pen: draw centre-to-centre lines or cell borders by dragging, or mark cells ✕ / ◯. Click a line to select the whole connected line of that colour.
  • Del removes the current mode's marks in the selected cells first. Press it again to clear everything else there.
  • Colour mode: click a coloured cell to select its whole same-coloured region.
  • With letters shown (or a letter puzzle), type letters to enter them. The letter shortcuts then need Alt.
  • Hold Shift for corner marks, Ctrl for centre marks
  • Ctrl+Z/Ctrl+Y undo/redo · Esc deselect
  • Click-drag to select several cells; Ctrl/Shift-click to add cells (even in other slices). Double-click a digit to select every copy in the cube.

Reading 3D clues in a slice

  • A + badge means a line, cage or dot continues into the next slice (index +1); − into the previous one.
  • Faint lines are clues in the neighbouring slices (toggle in Settings).

Setting puzzles

  • Switch to Set / Edit. Type digits to place givens.
  • Line tools: click or drag through cells; change slice with [ ] and keep clicking to continue the line in depth (any of the 26 neighbours). Enter finishes, Esc cancels.
  • Killer cages: select cells (Ctrl-click across slices), type the sum, press Enter.
  • Run Check solve path before sharing: it confirms the puzzle solves by logic alone (no guessing) and names the hardest technique needed. Fog of war needs the stored solution.

Rules

Solved!