Classic 9×9 Sudoku is one member of a much larger family of logic puzzles.
A Sudoku variant changes the classic format by adding constraints, replacing regions, changing grid size, or combining several grids — while usually preserving the core idea of placing symbols without repetition under a structured rule set.
This Guide is intentionally an overview, not a separate full vertical for every variant. If VeyraPlay later releases Killer, Jigsaw or another variant as its own game experience, that game can receive a dedicated Guide library without moving this page.
What makes something a Sudoku variant?
Classic Sudoku uses:
- a 9×9 grid;
- digits 1–9;
- nine rows;
- nine columns;
- nine 3×3 boxes;
- no repetition of a digit inside any row, column or box.
Variants change one or more parts of that model.
Four common ways variants change Sudoku
Add extra houses or placement constraints
Examples: Diagonal Sudoku, Hyper Sudoku, Anti-Knight.
Replace the standard regions
Example: Jigsaw/Irregular Sudoku.
Add arithmetic or relational clues
Examples: Killer, Arrow, Kropki.
Change or combine the grid
Examples: Mini Sudoku, 16×16 Sudoku, Samurai Sudoku.
Killer Sudoku
Killer Sudoku keeps the classic 9×9 row/column/box constraints and adds outlined cages with target sums.
The digits in a cage must add to the printed total, and common Killer rules also prohibit repeated digits inside a cage.
This creates a hybrid of placement logic and arithmetic combinations.
Classic candidate techniques still matter, but cage sums add a second source of eliminations.
Diagonal Sudoku / Sudoku X
Diagonal Sudoku adds the two long main diagonals as extra all-different units.
Each diagonal must contain digits 1–9 exactly once.
Rows, columns and boxes still behave normally; the diagonals add extra constraints rather than replacing anything.
This is one of the easiest variants to understand if you already play Classic Sudoku.
Jigsaw / Irregular Sudoku
Jigsaw Sudoku keeps rows and columns but replaces the nine rectangular 3×3 boxes with nine irregular regions of nine cells.
Each region must contain 1–9 once.
The logic is still Sudoku-like, but scanning feels different because region boundaries no longer align neatly with row/column bands.
Hyper Sudoku / Windoku
Hyper Sudoku keeps the normal 3×3 boxes and overlays four additional 3×3 regions, usually shown as shaded “windows.”
Each extra region also contains digits 1–9 once.
The extra constraints can create eliminations unavailable in Classic Sudoku.
Windoku is a common name for closely related window-style layouts.
Samurai Sudoku
Samurai Sudoku combines five overlapping 9×9 Sudoku grids.
Four outer grids share corner boxes with a central grid. Shared cells must satisfy the constraints of every grid they belong to.
The individual logic can remain classic, but the solving session is much larger and progress can transfer between overlapping boards.
Mini Sudoku: 4×4 and 6×6
Mini formats shrink the grid and digit set.
Typical examples:
- 4×4 using digits 1–4 and 2×2 boxes;
- 6×6 using digits 1–6 and commonly 2×3 regions.
The same all-different principle survives, making Mini Sudoku useful for short sessions and introductory puzzles.
Thermo Sudoku
Thermo Sudoku adds thermometer shapes.
Digits must strictly increase from the bulb toward the end of each thermometer.
Classic row/column/box rules still apply, while the thermometer imposes ordering constraints.
This type became especially prominent in modern online variant-solving communities.
Arrow Sudoku
In Arrow Sudoku, digits along an arrow usually sum to the digit in its circle.
The exact house rules remain classic unless the puzzle states otherwise.
Arrow constraints create arithmetic relationships without dividing the whole grid into Killer-style cages.
Kropki Sudoku
Kropki uses dots between adjacent cells to indicate numerical relationships, commonly:
- consecutive values;
- or a 1:2 ratio.
Different publications use white/black dot conventions, so always read the puzzle's rule legend.
Anti-Knight and Anti-King Sudoku
These variants borrow chess movement restrictions.
In Anti-Knight Sudoku, equal digits cannot be a knight's move apart.
Anti-King adds king-move adjacency restrictions.
These constraints change the peer graph: cells can interact even when they do not share a classic row, column or box.
Other modern variants
The ecosystem is much larger, including:
- Renban lines;
- German Whispers;
- Sandwich Sudoku;
- XV Sudoku;
- Palindrome lines;
- Consecutive Sudoku;
- Even/Odd constraints;
- 12×12 and 16×16 grids;
- combinations using several rules at once.
VeyraPlay does not need a separate Guide URL for every variant at this stage. This overview owns the discovery intent until a specific variant becomes a real editorial/game vertical.
Do classic Sudoku techniques still work?
Often, yes — but only after adapting the definition of a house/peer/constraint to the variant.
For example:
- Naked Singles still work wherever a cell has one legal value;
- subsets still work inside valid all-different houses;
- extra diagonal/hyper regions create additional candidate eliminations;
- Killer cages add arithmetic restrictions before or alongside classic logic.
Some named classic patterns rely specifically on rows, columns and 3×3 boxes and therefore need careful reinterpretation in non-classic region structures.
Are variants harder than Classic Sudoku?
Not automatically.
Extra constraints can make a puzzle more constrained, sometimes creating easier deductions even though the rules are more complex.
Difficulty depends on:
- puzzle construction;
- rule familiarity;
- required deductions;
- grid size;
- interaction between constraints.
A simple Sudoku X can be easier than a hard Classic Sudoku.
Which variant should you try first?
If you want a small change:
- Diagonal Sudoku;
- Hyper Sudoku.
If you want a geometry change:
- Jigsaw Sudoku.
If you want arithmetic:
- Killer Sudoku;
- Arrow Sudoku.
If you want a long session:
- Samurai Sudoku.
If you want a shorter grid:
- Mini Sudoku.
FAQ
How many Sudoku variants are there?
There is no fixed total. Puzzle designers continue to create new constraints and combinations, so the family is open-ended.
Is Killer Sudoku still Sudoku?
Yes. It normally keeps the classic row/column/box constraints and adds cage-sum rules.
Is Sudoku X the same as Diagonal Sudoku?
Usually yes: the two main diagonals are additional 1–9 units.
Is Jigsaw Sudoku harder than normal Sudoku?
Not necessarily. The irregular regions make recognition different, but actual difficulty depends on the puzzle.
Will VeyraPlay create separate Guides for every variant?
Not automatically. This overview presents the major families. A variant can receive its own full editorial vertical if it becomes a dedicated VeyraPlay game or demonstrates enough independent search/product demand.
What to learn next
If you are still building Classic foundations, use the Rules and How to Play Guides first. When VeyraPlay publishes a dedicated variant experience, its own Guides can take over detailed rules, techniques and strategy while this page remains the cross-variant discovery hub.