Techniques › Hidden Single › Practice
Practise the Hidden Single
A digit with only one home left in a house, even though that cell has other candidates.
8 real positions, each taken from an actual puzzle at the moment this was the cheapest move available. Two steps: find the cells that form the pattern, then find the candidate it rules out. A near miss tells you how many you had right, so getting it wrong is worth something.
| 7 | 6 | 17 | 8 | 24 | 9 | 5 | 13 | 24 |
| 5 | 8 | 249 | 3 | 24 | 1 | 249 | 7 | 6 |
| 29 | 13 | 249 | 6 | 7 | 5 | 1 | 249 | 8 |
| 37 | 2 | 8 | 179 | 5 | 6 | 149 | 49 | 47 |
| 4 | 1 | 157 | 79 | 38 | 378 | 239 | 6 | 257 |
| 6 | 9 | 57 | 2 | 13 | 4 | 8 | 1 | 57 |
| 12 | 57 | 26 | 17 | 1368 | 378 | 47 | 458 | 9 |
| 19 | 4 | 69 | 5 | 16 | 278 | 27 | 28 | 3 |
| 8 | 57 | 3 | 4 | 9 | 27 | 6 | 25 | 1 |
How to spot it
Take one digit at a time. For each box, cross off the rows and columns that already contain it. If exactly one cell survives, that is your placement. Boxes first — they are the easiest to scan and yield the most.
Full explanation on the Hidden Single reference page.
Practise something else
- Full House A house with one empty cell left. The first thing anyone learns.
- Naked Single A cell with only one candidate left.
- Pointing A digit confined to one line inside a box clears that digit from the rest of the line.