interesting chainmail combat rules

When two figures are within melee range (3"), one or several blows will be struck. The order of striking depends upon several factors. The man striking the first blow receives a return blow only if he fails to kill his opponent.
1st Round:
    First blow is struck by —
        a) the attacker, unless
        b) the defender has a weapon which is two classes higher, or
        c) the defender is fighting from above (castle wall, rampart, etc.).
2nd Round and thereafter:
    First blow is struck by —
        a) the side which struck first blow previously, unless
        b) the opponent has a weapon which is two classes lower, or
        c) the opponent is fighting from above.

A man wielding a weapon four classes lower (1 vs. 5, 2 vs. 6, and so on) strikes two blows during every melee round . If a man has a weapon eight classes lower, he will strike three
blows during every melee round.

a. For any weapon 2 or more classes higher than the attacker the ability to parry does not exist.
b. For any weapon 1 class higher to three classes lower than the attacker the defender may parry the blow by subtracting 2 from the attacker's roll, but he has no counter blow.

"Weapon Class", as defined in CHAINMAIL, corresponds to Weapon Speed Factor in AD&D

It's clear from these rules that should a dagger wielder fight a two handed sword, the swordsman will get the first hit but the dagger will be able to strike back multiple times a round. However, two people fighting with daggers would not get multiple attacks per round.  This is probably where the multiple attacks rule from Holmes' Basic came from, but those rules weren't clarified by the explanation from CHAINMAIL.

Heroes (and Anti-heroes) need never check morale, and they add 1 to the die or dice of their unit (or whatever unit they are with)...Heroes (and Anti-heroes) may act independent of their command in order to combat some other fantastic character...When meleed by regular troops, and combat takes place on the non-Fantasy Combat Tables, four simultaneous kills must be scored against Heroes (or Anti-heroes) to eliminate them.

The rules for heroes is interesting. They're a special unit that can be added to an existing rank and file, to give them a bonus die, such as the leader token from Advanced Squad Leader or a hero unit from Warcraft 3 or some MOBA. In mass missile fire, all the other figures in a unit must die before the Hero unit can be killed, but other Fantasy Creatures can attack heroes directly. The Hero's vaunted 4 consecutive hits to be killed protection only applies in standard, mass combat. In a wargame scenario with a large dice pool, scoring 4 hits is not hard, but it does afford the Hero unit plenty of protection, just not as much as you would assume coming from an RPG/D&D perspective.

The Man-to-Man and Fantasy Combat rules of CHAINMAIL are a mess. Every rule has a number of conditions and special cases to bear in mind while playing, and constant cross-referencing and page flipping is required in order to synergize them. As expected of Gygax.

The mass combat rules are actually a simple IGOUGO war game that is easy to remember and play, but has some funny balance issues between units.