Proven Sudoku
Techniques / Exotic and rank-zero
Table-Driven Methods
Also called Trebor's Tables, Exhaustive table methods, Truth tables.
New to this shorthand? How to read a sudoku grid explains r4c7, houses, candidates and the rest.
What it means
Work out ahead of time what follows from each single guess, and store it in a table. Then chains can be looked up instead of traced again and again. It is a speed trick for programs, not something to do on paper.
The exact rule, for stronger players
The rule, stated exactly: Enumerate the possible states of a bounded region exhaustively in a table, discard rows inconsistent with the rest of the grid, and read eliminations off the surviving rows.
What it removes: Remove candidates absent from every surviving row.
Why it works: Exhaustive enumeration over a bounded region. Sound by construction.
Worked examples
None yet. This pattern does not turn up in our daily boards, so there is no real example to show. We would rather wait than draw a fake one.
Learn these first
- Subset ExclusionThe same idea for any size of group.
Related exotic and rank-zero
- Broken WingA ring of squares where one number would have nowhere to go if the ring were perfect.
- Domino LoopA ring of pairs that lean on each other all the way round, like falling dominoes.
- Double ExocetTwo of those launcher patterns sharing the same numbers.
- FireworksA number is trapped so that it can only sit in one row, one column, or the square where they cross.
- Gurth's Symmetrical PlacementSome puzzles are built with a mirror pattern.
How often does it come up?
Our rough estimate: a computational aid. Named tables circulate on the forums for specific recurring configurations.