Sudoku Rules
7 articles
Girandola Sudoku: 9 Extra Cells Cut Givens from 24 to 21
Six dug girandola grids: a nine-cell pinwheel that replaces 3.5 givens, bans one digit from six cells at once, and passes once in 750 boards. Rules inside.
Anti-Knight Sudoku Rules: How the Knight Ban Cuts Clues from 25 to 14
We dug six anti-knight grids to the bone: the knight-ban replaces 11 givens a puzzle and creates sudoku's oddest opening. Full rules, geometry, and numbers.
Greater Than Sudoku: How 144 Inequality Signs Replace 23 Clues
We dug six grids to the bone: with every edge carrying a greater-than sign, the puzzle drops from 24.7 cell clues to one on average. Rules and order of attack.
Sandwich Sudoku Rules: How 18 Outside Sums Replace Cell Clues
We dug six tested grids to their minimum: eighteen sandwich sums cut the clue count from 24.7 to 12.2 on average. Full rules, the zero-sum trick, and the math.
Thermo Sudoku Rules: Why Clues Drop from 24 to 17
We generated six grids and dug each to its minimum: thermometers cut the clue count from 24 to 17 on average. Full thermo sudoku rules and window math inside.
Consecutive Sudoku Rules: How Bars Change Every Move
We measured 224 real consecutive bars on 6 engine-generated puzzles: 80% pin a cell outright while the no-bar rule strips candidates. Full rules inside.
Arrow Sudoku Rules: How to Solve Arrow Sudoku Puzzles
We generated 3 puzzles with our engine and measured the arrow rule on 54 real arrows. Here's how arrow sudoku works, with full grids and candidate math.