Edge template IV3c
From HexWiki
Template IV3c is a 3-stone 4th row edge template:
(From: www.drking.org.uk)
Defending the template
Red has two main threats, shown here with their respective carriers:
and
The second threat uses edge template III-2-e.
To try to block the connection, Blue must play in the overlap:
First attempt (d4):
Second attempt (b4):