Techniques · Expert

Swordfish

A swordfish is an X-wing with three rows instead of two. A digit is limited to the same three columns across three rows. It may not appear in every column of every row. Each of those rows uses two or three of the columns, and together the rows cover exactly three columns.

The digit is then removed from those three columns everywhere outside the three rows. The column version clears three rows instead.

When it shows up

Swordfish is Expert, one step past the X-wing. Mental is reserved for coloring and XY-chains.

No puzzle in the NYT archive needs a swordfish. Expert is where this site asks for fish at all.

See it on a real puzzle

The marks are the candidates left when this is the next step in the solve. Step through it: the pattern, what leaves, and what that forces.

See the pattern

Look at the 7s in these three rows.

6
5
4
1
9
7
5
9
6
1
9
8
6
5
8
3
6
1
7
2
4
5
9
9
7
1
4
3
5
8
2
6
2
4
5
9
8
6
3
5
6
9
1
4
2
8
4
6
9
5
3
1
5
2
9
6
4

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Related

X-wing