System's Twilight Hint Guide:

Ciruit Board Hints

Can you give me some general hints on solving this type of puzzle?

Note that all nodes will be used, and that the solution is unique. This means, for instance, that if you have a corner like , then the corner has to be used like . However, you can't connect like for then it would be equivalent to with two spaces left unused; i.e., there would exist an alternate solution that doesn't use all nodes. Therefore, the solution will look like , at least in part. Using similar reasoning, you'll often be able to deduce part of the answer.

Another method is to note that if you have a path that follows the border of the grid carefully, it is usually correct, even if it seems long. For instance, in the first puzzle, the path goes around the border and is correct, even though there is a direct, shorter .