Sudoku variants are easiest to compare by the rule they add or replace. Some keep the 9×9 grid and add cages or diagonals; others change region shapes, grid size or the relationship between neighboring cells.
What are the most popular Sudoku variants?
Popular Sudoku variants include Killer, Diagonal, Jigsaw, Samurai, 16×16, Mini, Thermo, Arrow, Hyper, Windoku, Anti-Knight and Even-Odd Sudoku. Choose Killer for arithmetic, Jigsaw for irregular regions, Diagonal for extra units, Samurai for overlapping grids and Thermo or Arrow Sudoku for directional constraints.
How do Sudoku variants compare?
| Variant | Main change | Best for |
|---|---|---|
| Killer | Sum cages | Combinations and arithmetic |
| Diagonal | Two extra 1–9 units | Classic logic with more intersections |
| Jigsaw | Irregular regions | Spatial scanning |
| Samurai | Five overlapping grids | Long linked solves |
| 16×16 | Sixteen symbols per unit | Large candidate sets |
| Thermo | Digits increase along paths | Ordering logic |
| Arrow | Path digits sum to a circle | Arithmetic relationships |
| Anti-Knight | Equal digits cannot be a knight’s move apart | Chess-like exclusions |
Which variants are closest to classic Sudoku?
Diagonal and Hyper Sudoku keep standard rows, columns and boxes while adding extra units. Jigsaw Sudoku keeps rows and columns but replaces boxes with irregular regions. These variants preserve most familiar candidate techniques.
Mini 4×4 and 6×6 Sudoku use the same uniqueness idea on smaller grids. They are good for learning unit interactions, although their reduced candidate sets create a different solving rhythm.
Which Sudoku variants use arithmetic?
Killer Sudoku adds no-repeat sum cages. Arrow Sudoku requires digits on a path to total the digit in its circle. Sandwich Sudoku gives sums of digits between 1 and 9 on each line. Little Killer places diagonal sum clues outside the grid.
Arithmetic narrows combinations, but classic uniqueness still applies. You rarely solve these variants by calculation alone; candidate positions and unit overlap remain essential.
Which variants use spatial or directional rules?
Thermo Sudoku makes digits strictly increase from a bulb along a thermometer. Renban lines contain consecutive digits in any order. Kropki dots describe consecutive or double relationships between neighboring cells. Anti-Knight and Anti-King rules forbid equal digits at chess-move distances.
Read every rule before assuming a familiar symbol. Variant authors sometimes combine constraints, and an unmarked adjacency may or may not imply the opposite relationship depending on whether a negative constraint is stated.
How should you choose a first variant?
Change one thing at a time. Try Diagonal for an extra unit, Jigsaw for new regions, Killer for sums or Thermo for ordering. Once the new rule becomes intuitive, combined variants become much easier to parse.
Our game / Story-led deduction
Want each placement to reveal part of a mystery?
Detective Sudoku is not classic Sudoku. It replaces digits and boxes with suspects, rooms and truthful spatial clues while retaining one suspect per row and column. Its real hints identify the clue behind a deduction instead of giving you the answer or solution.
See what makes Detective Sudoku different →Frequently asked questions about Sudoku variants
What is the easiest Sudoku variant to learn?
Diagonal Sudoku is approachable because it keeps all classic rules and adds only two extra units.
Which Sudoku variant is best without arithmetic?
Try Diagonal, Jigsaw, Hyper, Anti-Knight or Thermo Sudoku.
Is Killer Sudoku a Sudoku variant?
Yes. It combines classic uniqueness rules with no-repeat cages and target sums.
Can classic techniques work in variants?
Yes, whenever the relevant row, column or region constraints remain. Extra rules create additional eliminations.