How to Solve Sudoku: Hidden Triple

3 digits have only the same 3 cells between them to go in. Then the other notes in those 3 cells can be removed.

On Puzzle Lounge it appears from Hard up.

See it step by step

  1. A board full of notes. Look at the top box (the small digits are the notes, or candidates)
  2. Only the notes in the top box are left (the large digits are the notes)
  3. 2, 5 and 9 can only go in these 3 cells (no other cell has a note for 2, 5 or 9)
  4. These 3 cells are filled by 2, 5 and 9 (2, 5 and 9 must go somewhere in this box)
  5. So the other notes in these 3 cells can be removed (7 goes from row 2, column 4)

This is Oni No.366, partly solved.

Solve this puzzle →Print and solve →

How to find it

  1. Write out your notes (candidates).
  2. Pick a column (or row, or box) and gather the digits with 2 or 3 places to go.
  3. Among them, find 3 digits whose places add up to 3 cells, and remove the other notes from those 3 cells.

Things to watch

  • The 3 digits do not each have to fit in all 3 cells. It works as long as they have 3 cells between them.
  • This one is hard to spot. It helps to start with the columns that have few notes.
Read the full explanation

When, in a column, row or box, 3 digits have only 3 cells between them to go in, those 3 cells are filled by those 3 digits. The other candidates written in the 3 cells can be removed.

This is the Hidden Pair with 3 digits. Suppose that in a column, 2, 5 and 9 can go only in the 3 cells A, B and C between them.

2, 5 and 9 must go somewhere in this column, so A, B and C are filled by 2, 5 and 9.

So any notes in A, B and C other than 2, 5 and 9 can be removed.

In the top box, 2, 5 and 9 can go only at row 3, column 4, row 3, column 6 and row 2, column 4. These 3 cells are filled by 2, 5 and 9, so the other notes (7) can be removed.

Other techniques

Hidden SingleNaked SinglePointingClaimingHidden PairCage Combinations (Killer)Rule of 45 (Killer)Naked PairNaked TripleX-WingXY-WingSwordfishSkyscraper2-String KiteXYZ-WingW-WingJellyfish

For the basics and how to use notes, see how to solve sudoku, with tips. If you get stuck, the game's hints guide you step by step, starting with where to look.

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