All Sudoku Variants
9×9 · Misc

Color Sudoku

Also known as Colour Sudoku

Classic Sudoku with nine colours in place of the digits — the same puzzle, made friendlier for young solvers.

An example Color Sudoku: nine colours replace the digits — each row, column and box must hold all nine once.

Color Sudoku swaps the digits 1–9 for nine colours. Every row, column and box must contain each colour exactly once — the identical logic of Classic Sudoku, just painted instead of numbered. Because it needs no reading or arithmetic, it is the friendliest way to bring young children (and anyone new to the puzzle) into Sudoku.

The rule: nine colours, one each per unit

Fill the grid so that no colour repeats in any row, column or 3×3 box. That is the whole rule — exactly Classic Sudoku, with a palette in place of the number keypad. The box below is filled with nine distinct colours, one in every cell.

Nine colours stand in for 1–9 — each appears once per row, column and box.

It is the same puzzle as numbers

Assign each colour a number and a Color Sudoku becomes an ordinary number grid with no change to the logic. Every technique carries over untouched: scanning for a colour that can only go in one cell of a box is a hidden single; two cells that can only be red or blue are a naked pair. The picture below is the same box with the colours mapped to 1–9, to make the correspondence plain.

1 2 3 4 5 6 7 8 9

The same box with each colour mapped to a digit — colours or numbers, the puzzle is identical.

Who it is for

Color Sudoku shines as a first puzzle for children, who can spot a missing colour long before they would enjoy scanning digits. It is also a gentle on-ramp for adults who find a grid of numbers off-putting. One caution: because it relies entirely on telling colours apart, palettes should be chosen with colour-blind solvers in mind — well-separated hues, or colours paired with small symbols, keep it accessible.

Solving strategy

  • Scan for a missing colour. In each box, look for a colour that can only fit one empty cell — the colour version of a hidden single.
  • Think in numbers if it helps. Mapping colours to 1–9 lets you use every familiar technique unchanged.
  • Work row, column and box together. A colour barred from a cell by its row and column often has just one home left in the box.
  • Take it slowly with young solvers. One colour at a time builds the scanning habit that underlies all Sudoku.

Common mistakes

  • Thinking it is easier logic. It is the same difficulty as the equivalent number grid — only the symbols are friendlier.
  • Poor palette choices. Similar shades (two greens, two blues) make the puzzle unfair, especially for colour-blind solvers.
  • Forgetting the box rule. Each colour appears once per box as well as per row and column.
  • Guessing from the picture. As with numbers, Color Sudoku is solved by logic, not by how the colours look pleasing.

Can I play it here?

Not yet — Color Sudoku isn't one of the puzzle types SudokuStreak generates for now. But you can learn its rules above, and there's plenty here to sink your teeth into meanwhile: