Sudoku Variants Solver

Sudoku Variants Solver: rules, how to use it, tips

Classic sudoku — every row, column and box holds each digit once — plus one extra rule that depends on the variant.

All variants: each row, column and box (or jigsaw piece) contains every digit exactly once.
Sudoku X: both main diagonals also contain every digit once. Windoku: the four shaded 3×3 windows do too.
Jigsaw: the boxes are replaced by irregular pieces of the same size.
Kropki: a white dot joins digits one apart; a black dot joins digits where one is double the other; no dot means neither. XV: X joins digits adding to 10, V adding to 5; no letter means neither.
Anti-Knight / Anti-King: squares a knight’s move apart / touching squares never repeat a digit. Non-Consecutive: side-by-side squares never hold consecutive digits.
Even–Odd: grey squares are even, grey circles odd. Thermo: digits strictly increase from each thermometer’s bulb to its tip.
Sandwich: a number outside a row or column is the total of the digits between the 1 and the 9. Arrow: a circled digit equals the sum of the digits along its arrow. Little Killer: a number outside points down a diagonal and gives its total.
Consecutive Lines (purple): the digits on a line form a consecutive run in any order. Whisper Lines (green): neighbouring digits along the line differ by at least 5 (3 in a 6×6).

Choose the variant and size, then enter the givens and the variant clues (or press Sample).
Press Solve and step through: pencil marks, singles, the variant’s own rule, pointing digits, pairs and triples — with candidates shown.

Use the extra groups. In X and Windoku the diagonals and windows are full groups — look for hidden singles in them just like in boxes.
Pencil marks first. Variants make candidate lists shrink fast. Write them in, then apply the variant rule to each pair of squares.
Dots and gaps. In Kropki, a black dot can only be 1–2, 2–4, 3–6 or 4–8. A missing dot rules out both kinds — just as strong a clue.
Thermometer ends. On a thermometer of length 5 in a 9×9, the bulb is at most 5 and the tip at least 5.

The full guide, with a worked example and common mistakes: How to play Sudoku Variants.

Which variant should I start with?

Even–Odd or Sudoku X — they feel most like classic sudoku. Then try Jigsaw and Kropki.

Why are there no digits in some Kropki puzzles?

Because every dot is shown, the dots and gaps alone are enough to lead to one answer.

Is there always one answer?

Yes — every puzzle here is checked to have exactly one solution.

Can I enter a variant puzzle from a book?

Yes — open the Sudoku Variants Solver, choose the variant and enter the givens and clues.