| a | b | c | d | e | f | g | h | i | |
| A | 5 | 3 | 9 | ||||||
| B | 6 | 7 | 1 | 5 | |||||
| C | 5 | 4 | 9 | 2 | 1 | 3 | |||
| D | 8 | 4 | 9 | 3 | 7 | 2 | |||
| E | 1 | 3 | 7 | 9 | |||||
| F | 7 | 5 | 1 | 9 | 4 | 3 | |||
| G | 6 | 5 | 4 | 3 | 2 | ||||
| H | 6 | 7 | 3 | 2 | 9 | ||||
| I | 2 | 1 | 9 | 8 |
Naked Twins occur quite frequently and are often useful. Less common and less frequently useful are Hidden Twins. As the name suggests these are hard to spot. Here is such a puzzle. It was difficult to find one where a hidden twin helped to solve a square.
Running. Press the Stop button to pause the tutorial. Help page.
Welcome to a Sudoku Dragon tutorial. Use the bar under the grid to control how it is run. The buttons let you Stop; Play; Rewind back to start; Go back a step; Go forward a step.