Mass Combat in AD&D

File this one under “so easy I wonder why I didn’t think of this forty years ago.”

You have 80 Roman legionnaires packing short swords and chainmail with shields. You have 80 elite Austrian pikemen in dashing plate armor with rather stellar looking white collars. Who wins and at what cost?

Before we answer that, I want to highlight that this is in fact mass combat. Just for reference, in 1986, Steve Jackson defined “mass combat” as any rpg fight involving over 20 fighters– it’s right there in a sidebar in second edition GURPS! This is the same guy that figured out how to cram a Bulge game down onto a single piece of paper, so give him some credit here. For Steve and pretty much everybody else in the roleplaying space, “mass combat” means any battle so big it becomes too tedious to resolve with typical rpg combat systems.

Now, back to our legionnaires and pikemen. It turns out that AD&D can handle this scenario even better than it handles typical dungeon battles. It’s almost as if the game itself were somehow built around this scale of activity!

The trick is to think of each group of fighting-men as a collective entity. A mercenary soldier in AD&D has 4-7 hit points, which comes out to 5.5 on average. You can think of each unit of 80 men as having 44 hit points altogether– and then represent them on the tabletop with a set of eight figures. (Each figure represents ten men– the way Gygax dealt with things in the rather obscure volume of OD&D rules called Swords & Spells.)

Let’s give the Romans here a break and say that they won initiative in the opening round and manage to pull up in front of the pikemen two inches away so that they can hurl their spears without taking any attacks in return. The Austrian’s plate mail is AC 3, there is an AC Adjustment of -3 for spears thrown at plate, and there is a -2 penalty for medium range. A zero-level human fighter needs a 20 to hit AC 0. With that -2 for range added in, we are going to have to beg the DM to apply that to the armor class rather than to the die roll in order to have any chance to hit at all. Rolling a satisfying mass of 8 d20’s, it turns out that the question of what happens on a natural 20 here is a moot point, because they just aren’t happening!

During round two, the Austrians elect to charge the Romans. Chainmail and shield is AC 4 in AD&D. AC 4 gets an AC Adjustment of -1 when attacked by 13′ spears. During the charge, however, the Austrians get +2 to to-hit for their charge. The Austrians will hit on 16+ on a d20… and in this case I think it is reasonable for the second rank of figures to make an attack roll as well. The Austrians score two hits– and then roll a total of 7 for the damage.

Because the Romans have suffered an amount of damage slightly greater than the average hit point value of the men in their unit, they lose one figure.

Striking back to complete the round, the Romans are targeting AC 3 and take a -2 AC Adjustment for their short swords. Only their front rank may fight, so they get four rolls and need (again) natural 20’s to hit. They got one! Rolling a 3 for damage, this is NOT enough to remove a figure of the pikemen in return.

At this point, reality should be sinking in for the Romans. Even with hot dice, their opponents are hitting twice as often as they are. According to the DMG, this does call for a morale check. The base morale target is 50%. The Romans take a 10% penalty for “taking casualties without inflicting any” and another 10% penalty for “each friend killed”. A low roll is good here… but the Romans get 64 which is then modified to 84. They failed by 34! This results in “flee in panic” according to the morale results!

Well, this didn’t last long, but it is not entirely over. The Austrians get a set of parting shots before the Romans can break off from the melee. This will be against AC 5 because they no longer have a shield. The AC Adjustment is still -1. The bonus for striking at guys breaking off from melee is +4. The Austrians need 13+ to hit. Rolling 8 d20’s, they get three hits. Their damage totals 13 this time… which means the Romans lose two more figures. (They have done a total of 20 points of damage to the unit, but needed exactly 22 to remove 4 figures.)

Thus ends the combat in a mere three rounds– our marvelous Austrians holding the battlefield without even breaking a sweat. They are no doubt satisfied that the weird Armor Class Adjustment tables from the AD&D Players Handbook turn out to have some actual point for existing after all.