Game Development Reference
A full-size Twixt board with the four basic setups.
What should the opponent AI do in the face of these possible setups? When
possible, the most common counter is to ''hammer'' the first peg placed by
putting an opposing peg directly adjacent to the first peg in the setup and linking
to the newly placed peg. This requires that the opponent have an existing peg
from a prior move that is close enough to make the link to the new peg. While the
first side is setting up fancy moves, the opposing side is foiling them or cutting
them off with a carefully placed Twixt move. There are at most eight holes in
which to attempt to hammer the first peg, and not all of them are likely to be a
Twixt move from an existing peg from a prior move. If a hammer attack is
possible at all, there will usually be only a few holes that make it work. Looking
for a hammer attack narrows our search for a counter-move from hundreds to a
few. The hammer attack goes into the topic of moves alongside the four setups.
There are 484 opening moves, and we would like to trim that number down to a
more manageable number. In classic Twixt , the opening move is best placed