From the introduction:
The following rules are additions intended for more tactical play in D&D zero to second edition. The basic combat rules, while nicely tactical for small skirmishes, amount to little other than roll for initiative, I hack, you hack, and repeat until somebody drops from excessive blood loss.
The rules assume that dueling combat largely consists of properly exploiting openings that arise as the opponents maneuver. Aggression is useful, but must be balanced with caution and finesse, or swift death can arise from an unconsidered counter-stroke.
All standard D&D (or clone) combat rules apply except as [noted here].