Edge template VI2a

The edge template template VI2

Let us first see what possibilities Red has if he moves first.

There are two obvious options:

In both diagrams the possible intrusion points are marked by (+). So we only have to consider the intersection of the intrusion points. They are:

Intrusion at E5 and F5

If Blue blocks at E5 then Red plays F3, reducing to Template IVb

Likewise if blue blocks at F5:

Intrusion at E6

Red threatens to connect via D4. Blue must respond in one of the marked hexs.

The H4 piece is connected to the bottom with template III-1-a, and is connected to the top in two non-overlapping ways:

and