Expert technique · Technique Academy

Naked Quad

A naked quad is four cells in one unit whose candidates come from only four digits between them. It is the same idea as a pair or a triple, with a bigger party.

Professor Cryptic, the owl who teaches in the app
Professor Cryptic is thinking

The reasoning

Why does the Naked Quad work?

Those four digits are used up by the four cells, so no other cell in the unit can hold them. Look for cells with short, overlapping lists.

A worked example

What does the Naked Quad look like on a real board?

Naked Quad worked exampleA sudoku board with pencil marks. The Naked Quad uses R1C6, R2C6, R6C6, R8C6 and digits 6, 7, 3, 5 (column 6). The move strikes candidates 5 in R4C6, 5 in R5C6, 5 in R9C6, 6 in R9C6.4156726738996835435712327918184654625391584582456778625924513452541376372598652439871194875656238732561512569456
The move strikes candidates 5 in R4C6, 5 in R5C6, 5 in R9C6, 6 in R9C6. Digits 6, 7, 3, 5, column 6.
  • Cells that form the pattern
  • Cells that lose a candidate
  • Struck digit: ruled out

Make it stick

How can you practise the Naked Quad?

The Technique Academy in Cryptic gives every technique its own lesson and 5 practice boards that need exactly this move.

Get it onGoogle PlayPlay Cryptic on the web

Further reading: HoDoKu's page on this family of techniques.

EasierHidden TripleHarderHidden Quad