Sudoku variants
19 ways to break the same nine digits.
Every board here obeys ordinary sudoku: each row, column and 3×3 box holds 1–9 once. What changes is the extra rule layered on top. Some variants add lines across the grid, some join neighbouring cells with dots, some quietly forbid a shape — and each one rewrites what counts as a deduction.
If you are new, start with the plain Sudoku guide and then Golden Sudoku. Variants are harder mainly because your reflexes are wrong, not because they are unfair.
Rule variants
Thermo Sudoku
Digits rise along every thermometer.
Renban Sudoku
Each grey line holds a run of consecutive digits.
German Whispers
Neighbours on a whisper line differ by five or more.
Palindrome Sudoku
Read a grey line either way and the digits match.
Kropki Sudoku
White dots join consecutive digits, black dots join doubles.
XV Sudoku
X marks ten, V marks five.
Anti-Knight Sudoku
A knight move can never repeat a digit.
Windoku Sudoku
Four extra windows must also hold 1–9.
Arrow Sudoku
The circle equals the sum of its arrow.
Fog Sudoku
The board starts dark. Every correct digit lights up its neighbours.
Emoji Sudoku
Nine fruits instead of nine digits.
Sandwich Sudoku
The clue is the sum of everything between the 1 and the 9.
Skyscraper Sudoku
Buildings of height 1–9. The clue is how many you can see.
Material editions
Same sudoku, six surfaces. The rules do not change — the board does. Each edition has its own palette, texture and sound set, so the same puzzle feels different in the hand.
Sand Sudoku
Plain sudoku on a bed of warm sand.
Water Sudoku
Plain sudoku, digits dropping into still water.
Steel Sudoku
Plain sudoku engraved on steel.
Oak Sudoku
Plain sudoku on oiled oak.
Linen Sudoku
Plain sudoku stitched on cloth.
Bamboo Sudoku
Plain sudoku on split bamboo.