Lesson 02 · Sudoku Coach
Hidden Single Sudoku lesson
A digit has only one possible cell inside a row, column, or box.
The working method
- 1.Choose one digit and scan a complete row, column, or box.
- 2.Cross out cells where that digit is already blocked.
- 3.Place the digit in the only remaining position.
Evidence exercise 1 of 3
Find the proof, not the answer.
Select the evidence cell that make this Hidden Single deduction valid.
What to inspect
A digit has only one possible cell inside a row, column, or box.
Source puzzle · sudoku-0003
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.