Sudoku technique guide

Hidden Pair Sudoku Technique

A hidden pair is two candidates that only appear in the same two cells within one area. This guide explains the idea in plain English, when to look for it, and the common mistake to avoid.

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At a glance

Difficulty

Medium

This is where Hidden Pair normally sits in a human solving path.

Family

Subset techniques

It belongs to the subset techniques group of Sudoku logic.

Main action

Usually remove candidates

Most technique moves reduce notes first. That often reveals a simpler placement afterwards.

What is Hidden Pair?

A hidden pair is two candidates that only appear in the same two cells within one area.

The important thing is that this is logic, not guessing. You are using the current candidates to prove that a number must either go in one place, or cannot stay in another place.

In SudoSketch, this technique is designed to work with notes and Coach highlighting, so the key cells and removal cells can be shown clearly.

How Hidden Pair works

Look in one row, column or box.
Find two candidates that only appear in the same two cells.
Remove all other candidates from those two cells.

When to look for it

Look for Hidden Pair after easier moves have stopped working. First check for naked singles, hidden singles, locked candidates and simple pairs. If those do not move the puzzle forward, this technique may be worth checking.

For learning, do not try to scan for every advanced technique at once. Pick one method, understand the shape, and practise spotting that one pattern.

Common mistake

The two candidates must appear nowhere else in that row, column or box.

If you are unsure, rebuild the candidates first. Bad notes create bad logic, and Sudoku will absolutely punish you for it like a tiny spreadsheet goblin.

Hidden Pair FAQ

What is Hidden Pair in Sudoku?