Game Development Reference
While perfect play always results in a win for the hounds, the game is a pleasant
step up in richness compared to Tic-Tac-Toe .
There are many heuristics. The hounds start as an unbroken line. If they can
keep the fox behind their unbroken line, they cannot lose. If the fox does not
interfere, there is always a safe move for the hounds that keeps the line
unbroken. Early on, when the line is straight or nearly straight, the hound that
has only one possible move is the hound with the safe move. That hound is
found against an edge when all the hounds are on the same row. When the
hounds are in the middle of moving from one row to the next, the hound that
has one of its two moves blocked by the hound that moved last is the hound
with the safe move. In Figure 6.2, the right-most hound has the safe move. In
Figure 6.3, the fox is blocking a safe move from the left-most hound.
One heuristic for the fox is that any time it is behind an unbroken line, any move
that forces the hounds to break the line is better than any move that does not.
This is shown in Figure 6.3. It is clear that the fox must break the line to win,
and experience shows that there is nothing to be gained by waiting to break the
The fox forces the hounds to break their line on their next move.