Chimera: daily variant sudoku online, free

A chimera is a creature stitched together from several animals. Chimera sudoku stitches together two or three variant rule sets, so a single grid might have thermometers, an X-sudoku diagonal and parity shading all at once. It is the best way to play variant sudoku online free when you fancy a surprise.

Every day there is a new daily variant sudoku: Today’s Chimera, at Theorem rank, the same puzzle for everyone.

The rules

• Normal sudoku rules always apply: 1 to 9 once in every row, column and 3×3 box.
• On top, two or three rule sets from the other variants are combined. The rules for each puzzle are listed beside the board.
• At most one dot rule (Kropki or XV), one grid-wide rule (Sudoku X, Anti-Knight, Windoku or Non-Consecutive), one sum rule (Killer, Sandwich or Little Killer) and two line rules (Thermo, Arrow, German Whispers, Renban, Palindrome or Between Lines).
• Chimera can also include parity shading: a grey square holds an even digit and a grey circle an odd digit.
• Non-Consecutive is never paired with Kropki.

How to start

Read the rules first

Before touching the grid, read the rule list beside the board and say each rule to yourself. With three rule sets, forgetting one is the easiest way to get stuck.

Look where the rules meet

The best deductions in a chimera come from two rules acting on the same cells. Here a thermometer’s bulb sits on a grey square, which marks an even digit:

Let grid-wide rules do the scanning

If the chimera includes a diagonal, windows, knight’s moves or the non-consecutive rule, fold it into every scan. These rules have no marks, so they are the ones people forget.

Common mistakes

• Forgetting one of the rule sets halfway through.
• Mixing up the parity shapes: square is even, circle is odd.
• Expecting as many clues as in a single variant. Combined rules use fewer marks of each kind.

How the ranks scale difficulty

Every puzzle type on Hoot’s Puzzles comes in four ranks, named after the stages of a mathematical idea. Lemma is the warm-up: about a dozen more digits are given than logic strictly needs, and singles plus the variant’s own rule will carry you through. Proposition needs a real idea or two, typically pointing and claiming. Theorem is near-minimal, so almost every clue is load-bearing and you may need pairs. Conjecture gives the fewest digits and sparser rule clues: expect to think hard.

When rules are combined, each rule set uses fewer clue marks than it would on its own, so the grid stays readable and every mark matters. You can play chimera at any rank; the daily puzzle is always Theorem.

There are 99,999 puzzles per rank, each with its own number, so you can replay one or share it. Every type also has a 30-puzzle collection that climbs from Lemma to Conjecture. Every puzzle is checked to have exactly one solution that you can reach by logic alone, with no guessing.

Keep exploring

• Thermo SudokuDigits strictly increase from bulb to tip. Count the cells, bound the ends.
• Killer SudokuCages with sums instead of given digits. Partition arithmetic and the rule of 45.
• Kropki SudokuWhite dots for consecutive pairs, black for a 1:2 ratio. Missing dots matter.
• Solving techniquesSingles, pairs, cage arithmetic, line logic and Latin squares, all in one guide.
• All puzzle guidesEvery puzzle type on Hoot’s Puzzles, with rules and tips.