In Defense of THAC0
why do I even have to write this?
I grew up with AD&D and my first point of exposure was Baldur's Gate 2. I'm not a native English speaker and I was a kid at the time, so I played it localized into my first language. However, certain details like THAC0 weren't actually translated or explained in any way. For years I had no idea what it stands for or means, because it somehow didn't occur to me to look it up on the internet. I just didn't care enough, I guess.
Perhaps because I soon figured out it has to do with hit chance and that lower is better - once I understood that, it was enough for me. Nevertheless, I still had no idea about the underlying mechanics – absolutely none. So back in those days, it did indeed seem like some sort of bizarre, confusing, overly complicated mechanic. I was one of those people, who thought that THAC0 is just dumb and pointless.
And then I finally learned what the acronym actually stands for – "To Hit Armour Class 0". Suddenly the stat made sense, but somehow I still thought it was weird, arbitrary and unnecessarily complicated. I didn't truly sit down to properly think about it, and at a glance I just... didn't get it. I can't quite tell you why, but the logic of the mechanic somehow eluded me. Actually… no. In retrospect, I can tell you that, but but I’ll leave it for later.
What didn't help, was that I kept meeting and seeing people online, who hated THAC0 and rambled about how dumb and confusing it is. It was easy to just accept that and go with it. However, looking back it all seems beyond ridiculous.
And here's why.
[ THE MECHANIC ]
I am going to say this in bold full caps and a larger font for dramatic effect, because I’m an angry autistic internet person and I have to be unnecessarily animated about my autistic interests.
THERE'S ABSOLUTELY NO PRACTICAL DIFFERENCE BETWEEN THAC0 AND THE SYSTEM USED BY 5E FOR THE USER.
THAC0 ISN'T ANY MORE OR LESS COMPLICATED – THE REQUIRED CALCULATIONS ARE EXACTLY THE SAME.
And I can easily prove all of that, too.
First, let's look at the oh-so-popular 5e, which – I have to admit to disclose my bias – I quite despise on multiple different levels. But that aside... it's really simple. The character's Armour Class is the target of your dice rolls when trying to determine whether you managed to land an effective hit or not.
That is to say, if your opponent has the AC of 12, then you must roll 12 or higher to successfully land a hit on him. The only calculations you do are additions and subtractions of "to hit" modifiers or AC modifiers. So if your target is 12 and you have a +3 to hit modifier, then you simply add 3 to your rolls – thus, if you roll a 9, you still land a hit. It's that simple and players seem to like it. Which is okay.
What is not okay, is them acting as though THAC0 is something wildly different, outlandish and difficult. Or, really, something different at all. Because it's not. It's literally – LITERALLY – just an inversion of the 5e system. That is to say, your "to hit" is the target for your rolls and the enemy AC is the modifier you add or subtract.
Yes, that's it. That's actually it. There's nothing more to it than that. It's exactly the same thing, only in reverse.
Look, I can easily demonstrate it. THAC0 is a hard stat showing your universal hit chance against targets with NO armour modifiers, positive or negative. It’s the baseline target number for your hit rolls. If you have a character with a THAC0 of 12, that means that you need to roll 12 or higher to hit. And AC is simply a modifier here - either a bonus or a penalty for your roll. Or neither if it’s a 0.
Let's say you're fighting an opponent with the AC of 3. Well, it's a positive 3, a +3, so it means you get a +3 bonus to hit. In other words, you will add 3 to your rolls, meaning that if you roll a 9, you will still hit. And if the AC was a -3 instead, then that would be a penalty and you'd have to subtract the number from your roll, meaning that you'd have to roll at least a 15 to hit - because if you roll a 15 and subtract 3, you land at your target of 12. That’s it. AC in AD&D isn’t an actual armour value, but the same as saving throw bonuses. A modifier. And THAC0 is your baseline target for hitting an enemy without a modifier.
In other words… modern D&D gives every character a stat, which shows how good they are at resisting getting hit, and a modifier for their attacks. Classic AD&D gives every character a stat, which shows how good they are at hitting things, and a modifier for their defense. Or to put it yet another way, in one defense is primary and attack is a modifier, while in the other attack is primary and defense is a modifier.
[ THE AUTISTIC RANT ]
So, then... allow me to ask a simple question in a calm, civilized manner appropriate for a gentleman... HOW IN THE NINE BLOODY HELLS IS THAT ANY DIFFERENT?! You have your target number and you have your modifier to add or subtract. The math is exactly the same. You don't have to do anything extra. It's the exact same thing! So why, why, WHY do you internet people keep acting like the 5e system is some sort of amazing improvement? It's literally not in any way, shape or form. It's the exact same mechanic with different words attached, using a different framing, where AC is primary and "to hit" is a modifier, rather than the other way around.
Why do you have to act like these new versions of D&D are so much better in this regard, when they are just reinventing the wheel and enacting change for the sake of change? The only reason you've had issues with THAC0 - if you ever did at all - is because nobody has ever properly explained to you what it means, and that AC is a roll modifier, not a hard stat. It's the same as your saving throws. You have a saving throw vs wands +4. And you have an AC of -4. Saving throw bonuses are positive because you are making the throw and getting the bonus. AC bonuses are negative, because the enemy is making the throw and you're penalizing him. THAT'S IT. The end. It's that simple.
If you were having issues with it, you were just thinking about it the wrong way the entire time, looking at it from the wrong perspective. There's nothing else to this whole matter. It's not about intelligence, because if you have the capacity to understand the 5e system, then you have the capacity to understand the 2e system. THAC0 isn't "too complicated", it's just you throwing your hands up and claiming that it's too complicated, actively refusing to understand it. And that's what I absolutely despise - including in myself, when I used to do that. One last time... no, it's not more complicated, it's just a different framing of the same issue and if you struggled with it, you were too mentally lazy to try to understand the underlying logic, just brushing it aside instead.
And if it somehow isn't painfully obvious by now... that sort of behaviour pisses me off something fierce. I despise intellectual laziness and people not living up to their potential – deliberately choosing to not understand things, even though they can. That, to me, is one of the shittiest behaviours humans are capable of. Because while D&D is an utterly inconsequential thing, this shitty behaviour is by no means contained to it. It rears its ugly head in all aspects of life and I encounter it on a regular basis. People claiming that something is too difficult for them, just because it's different, and refusing to learn even though it's perfectly within their reach to grasp the issue. I can at least wave my hand at this when it's elderly people in their 70s and 80s (and yet many of them are still keen to learn!), but here we're talking about people in their 20s and 30s. It's absolutely fucking disgusting when young people act this way. Seriously vile. Just shut the fuck up, put down your dumb cat memes and TikTok, and use your brain for five seconds.
Don't get me wrong, though - you don't have to! Oh no, you don't have to put any effort into understanding anything. But then at least be honest about it. Don't claim that THAC0 is the most awful thing since Stalin and Hitler, and just admit that you don't give a shit about it and couldn't be bothered to understand the concept. How about that?
Oh, but that would hurt your precious ego, wouldn't it. You can't admit that you're a lazy fuck. Someone or something else has to be at fault. It's the damn THAC0 and the developers are so based for having had gotten rid of it, right?
Right.
[ THE CONSEQUENCES ]
But guess what?
I'm going to take this one step further.
Although in mechanical sense the two systems are interchangeable, I strongly believe that getting rid of THAC0 was detrimental to the franchise. Not because of any gameplay reasons, but because of identity reasons. THAC0 was completely unique. It was iconic. If you were given a single screenshot from a game and you saw THAC0 written anywhere, you instantly knew it was D&D. It was one of the unmistakable identifiers. A part of what made D&D, D&D. Virtually all RPG franchises have some form of AC, usually as a hard stat. But only D&D had THAC0 and AC as a modifier.
And that was good. As I have demonstrated, it was a perfectly functional system, just as functional as what has been used in the more recent editions. There was absolutely no technical reason to get rid of it. But it did have an immense identity value. And now, without it, D&D has become objectively more generic. Which is always bad for a franchise, because franchises need to stand out. Warhammer, Warcraft, D&D, Fallout, or any other major franchise you can name... they all have various unique aspects, which can be spotted at a glance and which set them apart from the others.
D&D has had a lot of unique stuff, like the iconic alignment system or indeed THAC0... but with the more recent editions all of that has been getting increasingly gutted or outright removed. Alignment barely matters anymore. THAC0 was cut entirely for no good reason. And so the franchise is severing its own roots, burning down its own traditions, and becoming less and less recognizable, slowly transforming into the most dull, boring "generic high fantasy" you can possibly imagine.
And isn't that fun, eh?
Reducing everything to the lowest common denominator in the name of "accessibility". Which honestly just means encouraging people's lowest impulses, rather than encouraging them to think and to be mindful.
THAC0 isn't really a test of intelligence compared to 5e, it doesn't take a smarter person to get it. It's just a test of the willingness to think at all. A test of openness and mental flexibility.
And those, who claim 5e is so much better for not having it, are simply people with the mentality and attitude to life of a bitter 75 year old man, who acts like a petulant child anytime something unfamiliar comes up.
You may think I am needlessly, excessively harsh, but it's the underlying truth of the matter. The whole THAC0 "debate" comes down entirely to the mentality of the people involved. I prefer THAC0 not because it's mechanically objectively better, but because it's mechanically equivalent, it has been there since the beginning of AD&D in the late 1970s, and was a defining, iconic feature of D&D as a franchise. My issue with 5e is not that I'm unwilling to adapt to it. I understand its system and I can work with it. But it's a pointless change for the sake of change, which has objectively made D&D more generic. That's not an opinion, but a fact – if a franchise has a unique feature and you take it away, you are by definition rendering it more generic.
And so, because D&D is close to my heart, I will always stand by THAC0, because it's one of the features, which gave it a unique flavour not found anywhere else.
[ Yes, I know that THAC0 has been removed long before 5e became a thing - back in 3e, in fact - but I chose to focus specifically on 5e, because that is the latest, most popular incarnation of this schismatic branch of D&D. ]
[ No, I don’t actually believe that 2e or 2.5e is just objectively better in every way - not at all. My stance is simply that while these could and should be improved, the official game took the wrong direction going forward. It’s just like with WoW - I don’t believe the old Vanilla / Classic is the best thing ever the way it is. I merely think the game was taken in the wrong direction beyond that point. My favourite version of WoW is “Turtle WoW”, a high quality fan-made modification and evolution of the original with tons and tons of very professional new content. ]
[ …and yes, I do consider 5e to be hot garbage, just like I consider retail WoW to be hot garbage. More on that at a later date. ]