Genius Academy / Level 1

LEVEL 1

Naked Single

One empty cell has only one legal candidate.

How to find it

  1. List the digits already present in the cell’s row, column and box.
  2. Remove those digits from 1–9.
  3. If one candidate remains, place 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