What's the difference between sudoku and color sudoku? Classic sudoku has 3 rules. Suirodoku adds a 4th — the color constraint — which creates 81 unique pairs instead of just 9 numbers, and unlocks new solving techniques.
The Key Differences
The Key Differences
Suirodoku takes everything you love about Sudoku and adds a revolutionary twist: colors. But it's not just a visual upgrade — it fundamentally changes how you think and solve.
Sudoku
- ○ Numbers only (1-9)
- ○ 3 constraints
- ○ 9 unique elements
- ○ Each number appears 9×
- ○ Classic techniques
Suirodoku
- ✓ Numbers + Colors
- ✓ 4 constraints
- ✓ 81 unique pairs
- ✓ No duplicates at all
- ✓ Exclusive techniques
The 4 Rules
The 4 Rules
Sudoku has 3 rules. Suirodoku has 4:
| Rule | Sudoku | Suirodoku |
|---|---|---|
| Row | Numbers 1-9 | Numbers 1-9 + All 9 colors |
| Column | Numbers 1-9 | Numbers 1-9 + All 9 colors |
| 3×3 Region | Numbers 1-9 | Numbers 1-9 + All 9 colors |
| Color group | — | Each color contains 1-9 |
The 4th rule is the game-changer: Each color (like all Green cells) must contain numbers 1-9. This creates a completely new dimension of logic.
81 Unique Pairs
81 Unique Pairs
In Sudoku, the number "5" appears 9 times — once per row. They're all identical.
In Suirodoku, the number "5" also appears 9 times, but each has a different color: Red 5, Blue 5, Green 5... Each is unique.
9 numbers × 9 colors = 81 unique pairs. No two cells are the same.
Exclusive Techniques
Exclusive Techniques
The 81 unique pairs enable techniques that don't exist in Sudoku:
- Rainbow Technique: Track a number across all 9 colors to find the missing color
- Chromatic Circle: Track a color across all 9 numbers to find the missing number
These techniques are impossible in regular Sudoku because there's no color dimension to track.
Which is Harder?
Which is Harder?
Suirodoku is not necessarily harder — it's different.
The extra constraint (colors) gives you more information to work with. Sometimes a cell that seems impossible in Sudoku logic becomes obvious when you consider the color dimension.
Think of it as Sudoku with a 4th dimension of logic at your disposal.
Which One Should I Play?
- New to puzzles? Start with classic sudoku to learn the 3 basic rules, then try Suirodoku.
- Sudoku expert looking for more? Suirodoku adds depth without changing what you love — same logic, new tools.
- Want faster solving? The 81 unique pairs actually give you MORE information per cell, not less.