Clue Complete
Once a clue already has all its required lines, every undecided side around it is an X.
How it works
- 1The clue is 1 and one side is already drawn, so this cell has all the line it is ever going to get.
- 2Anything else on its border would push the count past 1, which no later deduction can undo.
- 3Cross off the bottom, the left and the right.
- Edge on the loop
- Edge ruled out
- Cells that establish the pattern