Quick reference

This page lists every rule type and kind with a one-line meaning and a link to the page that defines it.

Type / kind	Meaning	Page
grid, box_grid, box, row, column	A house: a set of cells with no repeated digit	Houses and regions
region	A no-repeat cell set (diagonal, window, disjoint, colour, extra)	Houses and regions
cage	A no-repeat cell set, optionally with a sum	Cages and sums
sum: little_killer, frame, group, corner	A sum over cells where repeats are allowed	Cages and sums
line: thermo, slow_thermo	Increasing (strictly or not) from the bulb	Lines and arrows
line: whisper, renban, parity	Adjacent-cell conditions: difference, consecutive set, alternating parity	Lines and arrows
line: region_sum, palindrome, entropic, modular, zipper, between, lockout, double_arrow	Other line conditions	Lines and arrows
arrow	Shafts sum to the number in the bulb	Lines and arrows
edge: kropki, xv, difference, sum, product, ratio, greater	A clue on two adjacent cells	Edges and corners
corner: battenburg, mathrax, exclude	A clue on a 2×2 block	Edges and corners
sandwich, xsum, skyscraper, rossini, first_seen	A clue outside the grid about a row or column	Outside clues
neighbours	A pair rule over neighbouring cells of the whole board (antiknight, antiking, nonconsecutive, ...)	Whole-board rules
relation	Explicit pairs under one pair operator	Whole-board rules
negative	All clues of a family are shown; uncovered positions break the clue	Whole-board rules
cell: odd, even, low, high, set, exclude	A clue on single cells	Cell clues
contains, appears, clone, isomorphic, count, distinct_count, global_entropy, equal_sum, vudoku	Other families	Other rules
vendor rules (com.example:name)	Must-understand extension rules	Other rules
custom, table, allowed	Reserved and refused in format_version 1	Other rules