## very basic sashimi fish question

Advanced methods and approaches for solving Sudoku puzzles

### very basic sashimi fish question

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Please bear with me, I'm new and trying to understand: I'm referring to the Sashimi Fish main page in sudopedia...it depicts a sashimi swordfish "in the columns"...
it is not possible to form a complete Swordfish pattern
because it will degenerate into a single in r2c2 and an x-wing in columns 5 and 8.

Would some patient soul please explain what that means?
LeiSuLin

Posts: 6
Joined: 16 October 2008

### more...

I can see where it might make sense to me if it had said it would degenerate into an x-wing in columns TWO and FIVE...case 1: the candidate in r2c2 is true, which eliminates the candidates in r2c79, or case 2: eliminate the candidate in r2c2, leaving an x-wing in columns TWO and FIVE, which would eliminate the candidates in r58c8, leaving the only candidates in col8 in rows 1 and 3, also eliminating the candidates in r2c79...so I think I see how the eliminations occur....but the text says "5 and 8" not "2 and 5"...is there a typo?...or am I totally missing the boat?
LeiSuLin

Posts: 6
Joined: 16 October 2008

That sashimi swordfish description doesn't identify the candidates in r13c8 as fin cells. Then it doesn't tell you that degeneration to a single in r2c2 and an x-wing in c58 would occur if both fin cells were false (non-existent).
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` *-----------*  |./.|./.|.#.|  |.x.|./.|*/*|  |./.|./.|.#.|  |---+---+---|  |./.|./.|./.|  |.x.|.x.|.x.|  |./.|./.|./.|  |---+---+---|  |./.|./.|./.|  |.x.|.x.|.x.|  |./.|./.|./.|  *-----------* `
ronk
2012 Supporter

Posts: 4764
Joined: 02 November 2005
Location: Southeastern USA

ok...thanks....so the logic is, I guess, if both fin cells are false, then the x-wing in columns 5 and 8 eliminates the candidates in r58c2, producing the single in r2c2, which eliminates the candidates marked with the asterisks...and if either fin cell is true, the marked candidates are still eliminated....allright...the text explaining Sashimi Fish there at sudopedia could be a little clearer.
LeiSuLin

Posts: 6
Joined: 16 October 2008