Sudoku Tutorial

A swordfish is a 3x3 version of an X wing (2x2).

Swordfish:  three rows where a candidate is confined to three columns.  (or vice versa)

This swordfish is defined by the 5's in the rows 1, 6, and 9.   So the target cells are in the columns.

In rows 1, 6, and 9, candidate 5 is confined to columns 2,4, and 6.   This meets the definition of a swordfish.

The yellow squares are shown here to illustrate the
3 by 3 nature of the swordfish.  But notice that the 5 is missing from r1c2 and r9c2.  This still meets the definition of a swordfish (5's are confined to three columns in those three rows).  Candidate 5 is now committed in rows 1, 6, and 9 as well as column 2, 4, and 6.  

Any other 5's in those columns can be eliminated.

Although this is a great swordfish, can you see the
X-wing that is present here?    (click here to see it)

More swordfish information

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