< Hexagain


A bridge is when two pieces are “diagonally apart” from one another, with two empty cells between them.

While these pieces aren’t actually touching, white cannot separate them in a single move. If white plays between the stones, black can always play on the other hex.

If we annotate this situation, we can see that there are two disjoint paths between the stones, each of which require a single stone to become connected.

But since this pattern comes up so often, we’ll abbreviate this with the following notation instead: