Warband Rules

D&D started as a wargame (though not in the way most people like to claim). I know there is chainmail, and still need to really give it a good read, though it uses a different combat system than the D&D we're used to. I also know there have been several D&D mass combat rules published, of which I plan on checking out (BECMI & RC has some, Spells & Swords, ACKS, etc...). In fact I'm reading through ACKS right now because someone else was suggested it for the same reason I'm in the mood for wargaming.

I've been playing Mount & Blade: with Fire & Sword. Of course I love wargaming in general, but Mount & Blade always gets me in the mood for domain building D&D. Adventurer Conqueror King System (or ACKS for short) was designed from the ground up for this sort of play. D&D was actually meant for this sort of play, and it is very evident if you read the Little Brown Books. However, as time went on people enjoyed the adventuring, dungeon crawling, and role playing aspects more, so the theme of the game shifted. In any case, I've heard ACKS handles domain style D&D very well.

Regardless of how great ACKS is, I've been in the mood to tinker lately, and this idea just popped in my head for a mass combat system. A while a go I came up with a mass combat table for Swords & Wizardry (which has a simple mass combat system). I used a web site that gave dice statistics for rolling dice pools, and determine how many dice in the pool beat a target number. I don't recall the specific site I used, but I just dug this up, and it seems to do the trick: Scott's Dice Pool. The table would tell you how many of your troops hit, by comparing the dice to the target armor class, based on the appropriate probabilities.

Now the table I worked up was pretty nice, and it used the Ascending Armor Class system. Unfortunately I had only made the table up to AC 20, and had oddly made it down to AC 0 (which doesn't happen with Ascending Armor Class). I figured then, you could just calculate the Target Number (by subtracting the unit's Attack Bonus from the target's Armor Class) and compare your roll to that. This got me thinking of a simpler way of emulating the table; though it's not a perfect translation. As with most old school D&D, abstraction for the sake of simplicity and fun is never a bad thing.

This system requires Ascending Armor Class. Basically you would use the following formula for all attacks:

d20 + modifiers + troop advantage + 1 - AC = troops that hit

Troop advantage is how much the attack outnumbers the defender. The reason it's not just the difference, is it's easier to hit when outnumbering, but it's not impossible to hit when you are outnumbered. In other words, it keeps troops that are outnumbered from getting shafted.

This all makes sense because the number of troops that hit is how much you multiply damage by. For simplicity's sake, and so you don't end up rolling pools of dice, you would simply multiply the damage die (i.e. 10 x 1d8, instead of 10d8). Therefore outnumbered troops still have a chance of hitting, but don't do as much damage.

Another way of looking at it is: attack as you normally would, adding the number of troops outnumbering the target as a modifier. However much you beat the AC is how much you multiply the damage dice by.

After you figure out how many troops hit, and how much damage is dealt, subtract that from the total hit points of the unit. Figure out the average hit point value of the unit and divide the remaining hit points by that average (round up) to determine how many troops are left.

An example of the combat system would thus:

A group of 10 2nd level knights (1d8 long sword)  attacks a group of 7 0-level men-at-arms (AC 12 leather, 5 hit points each, 35 total). The knight's roll a 15 (d20) + 2 (attack bonus) + 3 (troop advantage), totaling 20. The difference is 8 (20 - 12 = 8). The knights then roll 3 on their d8, dealing 24 points of damage, leaving 3 troops [(35-24)/5 = 2.2 rounded up).

I did a stress of this with a mock combat. Both sides had AC18, and +0 attack bonus. This was, of course, meant to see how tedious it could be in extreme circumstances. It ended up taking 23 rounds of combat, 17 of which where nothing occurred. Now this seems pretty bad, but it only took 5 minutes all in all. Once damage does occur though, combat ends up getting pretty fatal, rather fast. I think this is a pretty realistic depiction to be honest. A bunch of inexperienced guys in field plate could go at it for about half an hour (assuming OD&D rounds) doing practically nothing to each other, then finally slaying each other rather quickly. If you assume B/X or 3E D&D it comes out to roughly 5 minutes, even more believable.

Something interesting to note, and pretty funny, is that damage occurred on round 1, almost like an immediate clash of arms, then round 6, 7, 19, 21, and 23; infrequently, then frequently. Keep in mind this was all just dice rolling, and no tactics or variation. Also it's highly unlikely you'd have two groups with AC18, but no attack bonus, or mounts even.

Obviously there is room for more playtesting and improvement, but for right now it's a simple and effective system, that  I really like.

Below is the log from notepad I used to keep track:

"Two groups of Knights, Field Plate with Long Swords

Assume HP 5 for each Knight, 10 troops each. Red vs. Blue.

Red has initiative every turn

Round 1; Blue takes 8 points of damage; Blue is at 42 hit points, 9 troops left

Round 2, 3, 4, 5, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 20, 22; nothing

Round 6; Blue takes 4 points of damage; Blue is at 38 hit points, 8 troops left

Round 7; Red takes 3 points of damage; Red is at 47 hit points, 10 troops left

Round 19; Blue takes 24(8 x 3) points of damage; Blue is at 14 hit points, 3 troops left

Round 21; Blue takes 8(8 x 1) points of damage; Blue is at 6 hit points, 2 troops left

Round 23; Blue takes 56(7 x 8) points of damage; Blue is defeated"