It is one of those things that fans of rules-light games can point to of proof that they are right. Why is it that a burly fighter can swing a two-handed sword at a troll with a single d20 roll, but if he tries to punch out a surly bartender, then everyone has to wait until percentages for every little thing that could possibly affect the outcome of the fight are calculated? It makes no sense. It's an attack! Why can't I just roll to hit and if the result is higher than my (THAC0 - my opponent's AC), I roll for damage? Why is that so hard to figure out?
2nd edition tried to clean things up a bit by requiring a normal attack roll. They even tried to simplify things further by having damage tied to the attack roll. Though I have to admit that it's a bit... confusing. A roll of 14 is a 'jab' for 2 points of damage, a roll of 16 is a 'glancing blow' for one point, and a 19 is a 'wild swing' for zero points. So an attack roll five points higher that a jab not only does less damage, it does no damage at all!
From my experience, there are two things that people want from an unarmed attack mechanic is:
- What is the base damage? and,
- What is the chance to knock someone out in one hit?
- Base damage is 1d2+Strength bonus/penalty. Per the 1e/2e DMG, only 25% of the damage is 'real' damage that heals normally. The other 75% is recovered after 1 hour of complete rest.
- In the event of a critical hit, the target must roll a saving throw versus paralyzation or fall unconscious for 1d6 rounds.
- Any character reduced to 0 hit points from punching damage falls unconscious for 1d6 turns. If the character also took normal damage, the character is not killed if real damage + 25% brawling damage does not exceed the character's total hit points.
- Gauntlets, brass knuckles and cestii always do normal damage, not brawling damage.
- Monks may choose to do either normal or brawling damage with their attacks.