Lesson 01 · Sudoku Coach
Naked Single Sudoku lesson
One empty cell has only one legal candidate.
The working method
- 1.Read the candidates in one empty cell.
- 2.Confirm that every digit but one is excluded by its row, column, or box.
- 3.Place the remaining digit; no guess is involved.
Evidence exercise 1 of 3
Find the proof, not the answer.
Select the evidence cell that make this Naked Single deduction valid.
What to inspect
One empty cell has only one legal candidate.
Source puzzle · sudoku-0001
Candidate marks reflect a verified intermediate state from this published grid.
Use mouse, touch, or keyboard. Arrow keys move focus; Enter or Space selects a cell.