## Finned X-wing?

Advanced methods and approaches for solving Sudoku puzzles

### Finned X-wing?

The following 3’s candidate grid came up in a recent puzzle after running through the basics. The candidate in r2c2, if false, would reveal two complementary X-wings, either of which would then eliminate the two candidates in r34c6, which is the correct solution. Candidate r2c2 doesn’t seem to fit the definition of a fin, so, short of trial & error, is there a single-digit rule (colors, chain, etc) that also eliminates these three candidates? Probably something simple, but can’t seem to spot it!

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`. . . | . . . | . . .3 3 . | . . 3 | . . .. 3 . | . 3 3 | . . .------+-------+------. 3 . | . 3 3 | . . .. . . | . . . | . . .3 . . | . . 3 | . . .------+-------+------. . . | . . . | . . .. . . | . . . | . . .. . . | . . . | . . .`
Sudtyro

Posts: 68
Joined: 21 December 2006

### Re: Finned X-wing?

Sudtyro wrote:Probably something simple, but can’t seem to spot it!
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`. . . | . . . | . . .3 3 . | . . 3 | . . .. 3 . | . 3 3 | . . .------+-------+------. 3 . | . 3 3 | . . .. . . | . . . | . . .3 . . | . . 3 | . . .------+-------+------. . . | . . . | . . .. . . | . . . | . . .. . . | . . . | . . .`

There are dual finned x-wings, but there are no eliminations.

Finned x-wing r26\c16 plus fin r2c2 would make eliminations r13c1<>3. Finned x-wing c25\r34 plus fin r2c2 would make eliminations r3c13<>3. But those cells contain no candidates.
ronk
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Joined: 02 November 2005
Location: Southeastern USA

### Re: Finned X-wing?

Nice to have the fin definition clarified. I'd assumed that a fin, to be a fin, would imply at least one elimination. Thanks for the feedback.
Sudtyro

Posts: 68
Joined: 21 December 2006