Step 3 of 5

Corners commit

A corner has two neighbors. Its little L is decided before you start.

The rule of thumb: A corner has just two neighbors, so its stretch of path is decided before you draw anywhere near it.

A board corner touches only two cells. Unless it holds dot 1 or the last dot, it needs two links and has exactly two neighbors, so it joins both. Four corners means up to four free L-shaped stretches on every board.

Do them first. Each L uses up an edge cell on both sides, and those cells now have a link in hand, which makes their own joins and eliminations easier. Edges tend to fill in this way, one forced cell after another.

A corner holding dot 1 or the last dot is the exception: those two need only one link, so leave them out. A corner holding any other dot still joins both neighbors. Each of these practice boards has three or more corners to commit.

Where to look: All four corners, before anything else. Skip any corner that carries dot 1 or the last dot.

Worked example

A real position from a board that needs Corners commit. Purple ring: what the reasoning rests on. Grey line: links already known. Dashed: the edges in question. Green line: a link it proves. Red cross: an edge it rules out.

The corner at row 1, column 1 (purple) touches only two cells. The dashed edges are the edges to them.

The corner at row 1, column 1 has only two neighbors, so it joins both.

Practice it ↓