Hidden Triple

Advanced7 min

Overview

A Hidden Triple is three digits that fit in only three cells of a house. Those cells must hold those three digits, so every other candidate in them can go.

How It Works

In one row, column or box, three digits can go only in the same three cells. Each digit needs its own cell, and there are just three cells, so the three cells hold exactly those digits. Any other candidate in them is wrong. A cell doesn't need all three digits, and a digit may fit just two of the three cells. Like every hidden subset, it has a naked mirror image in the same house: the house's other empty cells hold only the remaining digits.

When To Use It

Try it when simpler patterns run out, in a house where a few digits fit in very few cells.

How To Detect It

Go through a house one digit at a time and note where each digit can go. Find three digits that, together, fit in only three cells. Remove every other candidate from those cells.

Visual Example

Step 1 of 9

Three Digits, Three Cells

A Hidden Triple is three digits that fit in only three cells of a house. Those three cells must hold those three digits, so their other candidates can go.

Where to look

Pattern cells

Eliminations

Removed

7Solved

Key candidates

This step's candidates

Candidates already ruled out by earlier techniques aren't shown.

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Practice

Your goal: fill the highlighted cell. Select a cell, then pick a number.

A Hidden Triple is hiding here. Find three digits that fit in only three cells of a house, clear the other candidates from those cells, then fill the Hidden Single.Candidates already ruled out by earlier techniques aren't shown.

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Use it in a real game

Advanced puzzles are where these techniques start to matter.

Play an Advanced puzzle