Yeah, here it is. Chainmail is the missing piece from early D&D combat, I think - the real wargamer crunch. Reading OD&D without knowing this stuff is what has made me think you always have to referee a melee by the seat of your pants. It isn't until Red Box that the "alternate combat system" using d20 really starts to make sense. OD&D's default combat system, Chainmail's man-to-man rules, is actually pretty detailed and cool.
In each round of melee, each figure within range gets to trade blows. Melee rules 1-3 deal with who gets first blow. I think the way hits work is that on a hit the typical attacker rolls 1d6 for damage and the typical defender rolls 1d6 for hit points, so first blow is often the last blow. If there aren't situational modifiers, depends on your weapon class. Higher weapon class = long but unwieldy, with since 2 higher wins first blow in the first round, but 2 lower wins in subsequent rounds. Weapon classes range from 1 (dagger) to 12 (pike). You'd need to invent weapon classes for monster attacks - that's not really defined, as monsters are part of Chainmail's fantastic supplement, not part of the original design.
Rule 4 deals with parry. It depends on your weapon class.
Here are some ranges of weapon class disparity & how they can parry:
2 or more higher than attacker. (Morning star vs. sword, 2-handed sword vs. spear). No parry possible.
+1 to -3 within attacker's class. (Sword vs. mace to flail, battle axe vs. sword to spear). You can trade your counter-strike for subtracting 2 from the opponent's roll (on 2d6) - after the roll is made, I think, so parrying can save your life.
-4 to -7 lower than attacker. (Sword vs. spear, hand axe vs. sword). You can give up your first blow to parry. If, despite your parry, the attacker's second blow still hits, your lighter weapon breaks. If the parry is successful, and you survive the second blow, you can make a third blow in the round. It looks like, unlike within-class fighting, you'd have to declare your parry ahead of time.
-8 or more lower than attacker. (Mace vs. pike, dagger vs. halberd). You get the first blow automatically (after the first round of getting into range), and you can parry or strike with the second blow, but this parry only subtracts -1 and risks breaking the weapon. If the parry is successful and you survive the third blow, you can strike a fourth blow.
This all looks pretty interesting. I think it'd work well with the breaking shields rule, and if we're going to have multiple-hit-dice heroes where the first strike on the first round of combat isn't so deadly, we might want to add some extra damage to the slower weapons, like so:
Light weapons (one-handed, speed 1-3; a dagger or mace) - roll 2d6, use the lower
One-handed weapons (speed 4-7, a sword or flail) - roll 1d6
Two-handed weapons (speed 8-12, spears and 2-H swords) - roll 2d6, use the higher
I'll try playing some battle chess with my son using these rules this afternoon & see how they play. I think I'd ultimately want to convert it to a d20 roll, but then again there's something totally old-school and Traveller-esque about an interpretation of OD&D that doesn't even have funny-shaped dice yet.
