Genius Academy / Level 2

LEVEL 2

Hidden Single

A digit has only one possible cell inside a row, column or box.

How to find it

  1. Choose one house and one missing digit.
  2. Check every empty cell in that house.
  3. Place the digit when only one cell can accept it.

Logical demonstration

The violet cells represent the pattern; the gold cell represents the resulting placement or elimination. Verify every highlighted candidate belongs to the required houses before acting.

Common mistakes

  • Using cells that do not share the required row, column, box or peer relationship.
  • Removing a candidate before confirming every occurrence in the pattern.
  • Confusing a possible pattern with a completed logical proof.

Practise the technique

Open a real puzzle, keep candidate notes accurate and ask Genius Coach to identify the next supported logical move.

Practise on a puzzle