Hidden Single
The Hidden Single technique also uses pencil notes, but it’s a bit harder to spot the correct answer compared to Naked Single.
- Take a look at the pencil notes on this example.
- Now take a look at the highlighted block. We can see that number 1 appears inside of only one cell.
- It means that it is the only place for number 1 in the block.
- Hidden Single can also be applied in a column or row.
