Swordfish + Naked Triplet Sudoku Puzzles

Every puzzle below has Swordfish and Naked Triplet as its two hardest required moves, verified by a solver — 2,921 of the 65,284 puzzles in our library match. Rusty on either one? Drill them separately first: Swordfish practice · Naked Triplet practice.

Why these two appear together

This is the hardest pairing on the site, and the reason is that both techniques punish sloppy definitions. A Naked Triplet does not require each of its three cells to show all three candidates — cells reading 12, 23 and 13 qualify. A Swordfish does not require each of its three rows to have exactly three candidate cells — two is fine. Solvers who learned either as a tidy picture will find neither here.

Learned properly, both are containment conditions rather than shapes. The triplet says three cells hold three digits between them; the Swordfish says three lines hold a digit within three crossing lines. Stating them that way is what makes the degenerate cases visible, and these grids are built almost entirely out of degenerate cases.

Take the triplet first. Its eliminations are what reduce the digit's footprint to the three columns the fish needs.

Curated Swordfish + Naked Triplet puzzles

  1. Practice puzzle #1 — 25 givens · needs Naked Single, Hidden Single, Naked Triplet, Swordfish
  2. Practice puzzle #2 — 24 givens · needs Naked Single, Hidden Single, Naked Triplet, Swordfish
  3. Practice puzzle #3 — 25 givens · needs Naked Single, Hidden Single, Naked Triplet, Swordfish
  4. Practice puzzle #4 — 26 givens · needs Naked Single, Hidden Single, Naked Triplet, Swordfish
  5. Practice puzzle #5 — 26 givens · needs Naked Single, Hidden Single, Naked Triplet, Swordfish
  6. Practice puzzle #6 — 25 givens · needs Naked Single, Hidden Single, Naked Triplet, Swordfish
  7. Practice puzzle #7 — 25 givens · needs Naked Single, Hidden Single, Naked Triplet, Swordfish
  8. Practice puzzle #8 — 27 givens · needs Naked Single, Hidden Single, Naked Triplet, Swordfish
  9. Practice puzzle #9 — 23 givens · needs Naked Single, Hidden Single, Naked Triplet, Swordfish
  10. Practice puzzle #10 — 24 givens · needs Naked Single, Hidden Single, Naked Triplet, Swordfish
  11. Practice puzzle #11 — 25 givens · needs Naked Single, Hidden Single, Naked Triplet, Swordfish
  12. Practice puzzle #12 — 27 givens · needs Naked Single, Hidden Single, Naked Triplet, Swordfish
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Swordfish + Naked Triplet FAQ

How many Sudoku puzzles combine Swordfish and Naked Triplet?
2,921 puzzles in the Precision Sudoku library have Swordfish and Naked Triplet as their two hardest required techniques (beyond singles), out of a library of 65,284 solver-verified puzzles.
Why do I keep missing both patterns in these puzzles?
Almost certainly because you are matching shapes rather than checking conditions. Neither pattern requires the tidy full version — a triplet can be built from two-candidate cells, and a Swordfish row can contribute only two positions. Restate each as a containment rule and the degenerate cases become findable.
What makes this combination harder than the others?
Both halves have a common misconception attached, and the puzzles here rely on the degenerate form of each. There is no simpler route through, which is what makes them a genuine test of whether the definitions are understood rather than memorised.