Monday, August 4, 2014

Discussing D&D (1) – AD&D and understanding THAC0 and AC

A warrior surrounded by enemies, untouched
- Understanding THAC0 and AC -
(Summary TL;DR)

. Combat in AD&D was an abstraction, not the simulation of reality. One round represented 1 minute in the game world, while in most modern games, one round last around 5 to 10 seconds.

. A character's action was not the only action he would do in one round, but only the focus of its attention. In a round, a character would do many actions that would go without saying.

. THAC0 was an amalgamation of a character's skill, technique, luck, positioning, strength, reach, stamina, and all other qualities necessaries that would make a person able to deliver damage dealing blows.

. AC was the capacity of resisting the force of an impact, foresee the enemy's moves, the extension of how much the armor was covering the character's body, how tough was the material, how hard was it to hit the target (in terms of size, speed and mobility) and how thick was the armor's covering layer.

!As always, remember to comment and tell what you though about the subject!


I wish to discuss in this post about something that I find much necessary, at least for those who still play Old School rpgs or read about them. I heard many a time – and I believe that many of you might have heard something similar – about how 'unreal' or 'incoherent' combat is in D&D, specially with old school D&D (like 1 st edition and AD&D). I heard things like: 'how can a human warrior fight against a gigantic colossus without the creature just kicking him away?'; 'what about those hit points? As long as you have 1 hit point, you are fine, even if you lost 100 of them'; 'how the heck does having high armor makes you harder to hit?'. Many answer such remarks saying that 'D&D is a heroic game', using that as an excuse.

And, even so, when we face old editions – like AD&D – we see things that even D&D gamers find hard to believe. For example, there were no targeted attacks in AD&D (unless you were using optional rules found elsewhere the Dungeon Master Guide). Another example would be with the bonus of Dexterity in AC was not lost if you were using heavy armor, even full plate. Such things seem to put AD&D's combat in a very conflicting position with reality.

Here is the point: combat in AD&D, although it might seem at first glance unrealistic, it truly is not. I would even dare to say that AD&D is more realistic than 3 rd edition D&D and even Gurps (gasp! I know, I might be overstating just a little bit here, eh?). But hold on a minute, allow me to elaborate that argument by discussing about the two main aspects of combat in D&D – Attack (THAC0, in AD&D) and Armor Class (AC).

But before talking about those two, the first thing to notice is how much it takes a Round in AD&D to complete, a detail many times forgotten. In most contemporary rpgs, a round takes about 5 to 10 seconds to complete. In Gurps, it's just 1 second; in d20 D&D, it's 6 seconds. But, in old AD&D, it took 1 MINUTE. Yes, 1 minute; or 60 seconds; or 60 times longer than GURPS, 10 times longer than d20 D&D.

With that said, we clarify an important aspect of AD&D – it tries not to emulate the reality of every single blow and action a character does during a round, but, in fact, it's an abstraction of a combat situation. When during combat you declare your intention, this does not mean that your character will do ONLY what you said, but that it will FOCUS on what you said. So, if you say that your character will drink a potion, your character will have to take it off from its bag, look around, wait for an opportunity, take off the lid, drink it, all of that while evading, parrying and dodging attacks.

Based on that idea, we can finally understand what THAC0 meant in AD&D. It was everything concerning the capacity of a character to deal a damaging blow in one opponent: its size, strength, skill, technique, positioning and stamina. Because of that, a Troll with THAC0 13 (+7 attack) would be as capable in combat as a warrior of level 7. Its ferocity, size and brutality were counted on its THAC0. When you would make an attack roll using your THAC0, that did not mean you were delivering ONE single blow, but, in fact, that you were engaging in direct combat with many maneuvers, feints, blows and, in case of a hit, the damage would represent the sum of all those strikes that connected and all the damage the warrior was able to inflict. It's for that reason that AD&D did not have rules for targeted attacks – the attack roll meant the best attack that you could have made during your turn.

A Leviathan AC does not mean that it's hard to hit...
but that it is hard to hurt!
In the same way of THAC0, AC was not only the type of armor you wore, but also how thick was a monster's hide, how hard it was to be struck (because of size, speed, mobility), how much did it cover its body and other factors like those. Everything that could make it hard for a blow to cause real damage to a creature was part of its AC. That is the reasoning behind the base 10 of AC – it depicts a person trying to evade and not be hurt, a creature blocking and enduring damage. That's why a whale had AC 4 in AD&D (16 in ascending rules) – not because it was hard to hit it, but because its sheer size and thickness made it very hard to cause real damage do the creature. Meanwhile, the Will-o-wisp had AC -8 (28), because it was very agile, tiny and its body was
made of electricity and light.

The macabre Will-o-wisps from AD&D
- The Balls of Steel - 
I hope that with this post I have clarified – both for players new and old – this point of debate around the 'incoherence' of D&D's combat. It might not be as realistic as GURPS, but it is interesting to know the logic behind its rules. I still find that system of combat one of the best ever created – but that is a matter of personal opinion. I intend to talk about other subjects regarding D&D combat in future posts, like Hit Points and Saving Throws.

Until then,


If you liked this post, you may help me improve by sharing it in your social networks. Also, if you are curious, give it a look at my others works and consider becoming my patreon.

No comments:

Post a Comment