Armor Class

[Havard]

From what I understand, Dave Arneson replaced the Chainmail Combat System with a rule system using the Armor Class Mechanic which he based on concepts from a naval combat game called Civil War Ironclads.

It seems to me that this was a pretty brilliant move. I dont know much about Chainmail, but so many other RPGs involve an attack roll, followed by a defense roll. One of the advantages of AC is that you eliminate one of the dice rolls, speeding up combat considerably.

The odd side of AC in D&D is of course that it doesnt distinguish between attacks that miss the opponents and attacks that hit, but dont cause damage.

What do you think of the Armor Class rules?

-Havard

[finarvyn]

1. "Civil War Ironclads" was, as I remember it, a game also written by Dave but never published.

2. I think that the attack value versus defense value (which was also the main combat system behind most Avalon Hill and SPI wargames of the era) is much more efficient than what later RPGs put together in the name of "realism." Adding in parry or dodge or armor absorption rules simply slows the whole process down.

3. As to AC, I still have frustration that low is better and this is a rule I "fixed" decades ago in my own game. I can see where it comes from, however, when "First Line" or "First Class" ships were the best ones, "Second Line" were second best, and so on. Logical in context, perhaps, but illogical in a RPG, unless...

4. ...my personal theory is that one of the early combat systems goes back to 2d6 and trying to roll under AC to hit. This also explains why the best AC in the original game was 2 instead of 1. So, to hit an unarmored foe (AC9) you would have to roll 9-12 on 2d6, but to hit someone in plate and shield (AC2) you would have to roll 2 on 2d6. I would still have reversed it (let plate & shield be AC12 and unarmored be AC5, for example) so you would roll under, but that's just one guy's preference.

[RobJN]

The odd side of AC in D&D is of course that it doesnt distinguish between attacks that miss the opponents and attacks that hit, but dont cause damage.

What do you think of the Armor Class rules?

-Havard

I think they work just fine.

In my games, I ruled a roll of 1-9 a complete miss (no contact); hits 10+ but not the number needed to hit AC glanced off the armor to little effect. (If the opponent was unarmored, or less heavily so, these hits could have dealt damage) Only hits that matched or beat AC got through to do damage (be it actual armor penetration or just heavy bruising through the armor was up to the player-DM interaction and weapon type). If the character has a shield, a would-be hit that misses the improved AC by 1 point is taken/brushed aside by the shield.

Gilliam wears leather armor (AC7); he has a dexterity of 16, bringing his AC down to 5. He is fighting a kobold, which needs a 14 or better to hit him. If the DM rolls 1-9, the kobold misses completely. 10-11, it would have hit, but Gilliam ducks or dodges aside (Dex bonus). A roll of 12 or 13 means the kobold's rusty short sword scrapes off Gilliam's leather breastplate. A 14 or better indicates the kobold gets lucky and lands a strike.

Admittedly, Gilliam should probably invest in some chainmail, (he's a fighter, not a thief!) but that's just not in fitting with the rest of his character

For monsters, it can be a bit harder to tell, because they don't have a dexterity/armor type breakdown. But the general rules apply, I think: less than 9 misses, 10+ would make contact, but be brushed aside bounce off, depending on the creature type. Tough hide? Armored plating? Scales? Kobolds and goblins being so small, I usually attribute "near misses" to them ducking and weaving out of the way.

It doesn't go into the tedium of armor itself taking the damage, and thus needing repair, like a certain other system, although such rules could easily be bolted on.