--- document: home name: Open Rules url: https://rules.sudoku-sleuth.com/README.md --- # Open Rules Give each rule a name and say where it applies. A case file declares the library root once; each name resolves to its rule page under that root. Custom rules carry their full definition in the case file. Each published rule keeps its meaning. A new meaning gets a new kind. [Shared predicates](https://rules.sudoku-sleuth.com/predicates.md) define the mathematical notation. Cells use r1c1 notation. Repeated rules have numbered IDs; singleton rules use their kind as the implicit ID. Drawings refer to IDs; their colours and shapes do not change the rule. - [shifter-line](https://rules.sudoku-sleuth.com/shifter-line.md) - [summit](https://rules.sudoku-sleuth.com/summit.md) - [thermo](https://rules.sudoku-sleuth.com/thermo.md) - [whispers](https://rules.sudoku-sleuth.com/whispers.md) - [parity](https://rules.sudoku-sleuth.com/parity.md) - [modular](https://rules.sudoku-sleuth.com/modular.md) - [entropic](https://rules.sudoku-sleuth.com/entropic.md) - [renban](https://rules.sudoku-sleuth.com/renban.md) - [nabner](https://rules.sudoku-sleuth.com/nabner.md) - [palindrome](https://rules.sudoku-sleuth.com/palindrome.md) - [slow-thermo](https://rules.sudoku-sleuth.com/slow-thermo.md) - [between](https://rules.sudoku-sleuth.com/between.md) - [lockout](https://rules.sudoku-sleuth.com/lockout.md) - [arrow](https://rules.sudoku-sleuth.com/arrow.md) - [double-arrow](https://rules.sudoku-sleuth.com/double-arrow.md) - [zipper](https://rules.sudoku-sleuth.com/zipper.md) - [region-sum](https://rules.sudoku-sleuth.com/region-sum.md) - [index-line](https://rules.sudoku-sleuth.com/index-line.md) - [bremban](https://rules.sudoku-sleuth.com/bremban.md) - [close-whispers](https://rules.sudoku-sleuth.com/close-whispers.md) - [primality](https://rules.sudoku-sleuth.com/primality.md) - [line-choice](https://rules.sudoku-sleuth.com/line-choice.md) - [limited-digits](https://rules.sudoku-sleuth.com/limited-digits.md) - [allowed-digits](https://rules.sudoku-sleuth.com/allowed-digits.md) - [mean-lines](https://rules.sudoku-sleuth.com/mean-lines.md) - [greek-carpet](https://rules.sudoku-sleuth.com/greek-carpet.md) - [pointing-thermo](https://rules.sudoku-sleuth.com/pointing-thermo.md) - [kropki](https://rules.sudoku-sleuth.com/kropki.md) - [pair](https://rules.sudoku-sleuth.com/pair.md) - [quadruple](https://rules.sudoku-sleuth.com/quadruple.md) - [extremum](https://rules.sudoku-sleuth.com/extremum.md) - [parity-cells](https://rules.sudoku-sleuth.com/parity-cells.md) - [counting-circles](https://rules.sudoku-sleuth.com/counting-circles.md) - [molecules](https://rules.sudoku-sleuth.com/molecules.md) - [tardis](https://rules.sudoku-sleuth.com/tardis.md) - [pressure-gauge](https://rules.sudoku-sleuth.com/pressure-gauge.md) - [pointing-arrow](https://rules.sudoku-sleuth.com/pointing-arrow.md) - [coordinate-arrows](https://rules.sudoku-sleuth.com/coordinate-arrows.md) - [value-modifier](https://rules.sudoku-sleuth.com/value-modifier.md) - [cage](https://rules.sudoku-sleuth.com/cage.md) - [equality-cage](https://rules.sudoku-sleuth.com/equality-cage.md) - [layered-cage](https://rules.sudoku-sleuth.com/layered-cage.md) - [remainder-cage](https://rules.sudoku-sleuth.com/remainder-cage.md) - [product-cage](https://rules.sudoku-sleuth.com/product-cage.md) - [sum-free-cage](https://rules.sudoku-sleuth.com/sum-free-cage.md) - [look-and-say](https://rules.sudoku-sleuth.com/look-and-say.md) - [vault](https://rules.sudoku-sleuth.com/vault.md) - [n-mate](https://rules.sudoku-sleuth.com/n-mate.md) - [equal-sums](https://rules.sudoku-sleuth.com/equal-sums.md) - [cage-shapes](https://rules.sudoku-sleuth.com/cage-shapes.md) - [cage-pair](https://rules.sudoku-sleuth.com/cage-pair.md) - [cage-expressions](https://rules.sudoku-sleuth.com/cage-expressions.md) - [little-killer](https://rules.sudoku-sleuth.com/little-killer.md) - [sandwich](https://rules.sudoku-sleuth.com/sandwich.md) - [x-sum](https://rules.sudoku-sleuth.com/x-sum.md) - [skyscraper](https://rules.sudoku-sleuth.com/skyscraper.md) - [numbered-room](https://rules.sudoku-sleuth.com/numbered-room.md) - [run-sum](https://rules.sudoku-sleuth.com/run-sum.md) - [outside](https://rules.sudoku-sleuth.com/outside.md) - [ordered-block](https://rules.sudoku-sleuth.com/ordered-block.md) - [doll-sum](https://rules.sudoku-sleuth.com/doll-sum.md) - [unique](https://rules.sudoku-sleuth.com/unique.md) - [clone](https://rules.sudoku-sleuth.com/clone.md) - [index](https://rules.sudoku-sleuth.com/index.md) - [constructed-regions](https://rules.sudoku-sleuth.com/constructed-regions.md) - [anti-knight](https://rules.sudoku-sleuth.com/anti-knight.md) - [anti-king](https://rules.sudoku-sleuth.com/anti-king.md) - [diagonal](https://rules.sudoku-sleuth.com/diagonal.md) - [negative](https://rules.sudoku-sleuth.com/negative.md) - [scoped-move](https://rules.sudoku-sleuth.com/scoped-move.md) - [same-class](https://rules.sudoku-sleuth.com/same-class.md) - [window-classes](https://rules.sudoku-sleuth.com/window-classes.md) - [diagonal-lines](https://rules.sudoku-sleuth.com/diagonal-lines.md) - [hidden-modular](https://rules.sudoku-sleuth.com/hidden-modular.md) - [flat-mates](https://rules.sudoku-sleuth.com/flat-mates.md) - [rotational-sums](https://rules.sudoku-sleuth.com/rotational-sums.md) - [magic-square](https://rules.sudoku-sleuth.com/magic-square.md) A standard board is one line: [sudoku 9x9](https://rules.sudoku-sleuth.com/sudoku.md). The short names [whisper](https://rules.sudoku-sleuth.com/whisper.md) and [killer](https://rules.sudoku-sleuth.com/killer.md) refer to whispers and cage. [Rule-line syntax](https://rules.sudoku-sleuth.com/syntax.md) describes not, if and unless. The general rules [Yin Yang](https://rules.sudoku-sleuth.com/yin-yang.md) and [absent digits](https://rules.sudoku-sleuth.com/absent-digits.md) express shading and missing digits.