Proven Sudoku
Bent Naked Subset
Also called Bent Subset, Almost Locked Candidates (related).
New to this shorthand? How to read a sudoku grid explains r4c7, houses, candidates and the rest.
What it means
A group of squares bent across two rows, columns or boxes. They hold one more number than there are squares. All but one number is locked in place. That last one has to land inside the group, so squares seeing all its homes lose it.
The exact rule, for stronger players
The rule, stated exactly: A naked subset whose cells span two houses rather than one. If the subset of n cells covers n+1 digits and all cells containing the extra digit lie in the intersection of the two houses, that digit is eliminated from cells seeing all of them.
What it removes: Remove the extra digit from cells seeing every cell of the subset that contains it.
Why it works: A subset confined to one house forces its digits. Bent across two houses it falls one short, so exactly one digit escapes. Constraining where that digit can sit yields the elimination.
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
- Naked Subset (general form)Find some squares in one row, column or box.
- Locked Candidates (general form)Sometimes all the spots for a digit inside one group also sit inside a second group.
Related wings
- Letter-named wings (M, S, L, H, Split, Hybrid, Local)Short chains that people gave letters to.
- Remote PairsA string of squares that all hold the same two numbers, each one linked to the next.
- VWXYZ-WingThe same idea stretched to five squares and five numbers.
- W-WingTwo squares far apart hold the same two numbers.
- WXYZ-WingFour squares holding four numbers between them.
How often does it come up?
Our rough estimate: this is a unifying page rather than a separately hunted pattern. Its value is showing that XY-Wing, XYZ-Wing and WXYZ-Wing are one idea.