Let's Talk About THAC0

Morrus

Well, that was fun
Staff member
In my experience, THAC0 doesn't have a reputation at all, if by "reputation" you mean "opinion held by people without direct knowledge." People either know what THAC0 is because they played 2E, or they didn't play 2E and have never heard of it.
That’s not my experience.
 

lowkey13

I'm sorry, Dave. I'm afraid I can't do that.
Mathematically, people do addition faster than subtraction. d20+bonus >= target is super quick at the table. The addition is quick, the comparison to target is quick. Subtraction or table lookup is slower.

Also, d20+bonus >= target is quite intuitively obvious. Especially among new players the chance of success (knowing bonus and target) is clearer without working it out.

THACO doesn't seem to bring any advantages to offset either of these, much less both.
Let's see-

Scenario A:

So, um, let's look at the d20+Bonus >= target AC. You know, the, um, DuhtwentyBuhTAC! So, what's your DuhtwentyBuhTAC* look like?


Scenario B:

THAC0, baby, YEAH!


Game.

Set.

Match.

THAC0.



*In fairness, I might start saying this. DutwentybuhTAC has a nice ring to it, even if it's no THAC0. I mean .... I can just see my new, elite, super-bowl winning character.
You know, Joe Thac0.
 
It's not an "argument" that addition is easier than subtraction. It's a proven fact.

Also, it's not an "argument" that consistency makes it easier for people to learn (higher numbers always better). That's also a proven fact.

THAC0 fails both and belongs in the dustbin of history.
 

Umbran

Mod Squad
Staff member
I hope another dozen people explain to me that addition is easier than subtraction! :)
Be careful what you wish for...

Nevertheless, I still maintain my position that THAC0 is not as complex as it’s reputation would lead you to believe, whether or not addition is easier than subtraction.
Are you sure the reputation is "more complex", and not just "more confusing"?

But, note that in your explanation, you left out a step:

In 3E-5E, you roll d20 and add bonuses in order to beat the target's AC.

In 1E-2E, you roll d20 and add bonuses (Strength, magic, etc) in order to beat THAC0 minus AC.​

So, in 3E-5E, you do one mathematical operation, on the roll total. In 1E-2E you generally do two - one on the die, one on the target number. And that "minus AC" in general also included the fact that the AC could be a negative number.

Whether you decide that this is not "as complex as its reputation". It does literally require more operations.
 
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lowkey13

I'm sorry, Dave. I'm afraid I can't do that.
It's not an "argument" that addition is easier than subtraction. It's a proven fact.

Also, it's not an "argument" that consistency makes it easier for people to learn (higher numbers always better). That's also a proven fact.

THAC0 fails both and belongs in the dustbin of history.
For forty-three years of my conscious life I have remained a revolutionist; for forty-two of them I have fought under the banner of THAC0. If I had to begin all over again I would of course try to avoid this or that mistake, but the main course of my life would remain unchanged.

I shall die an AD&D revolutionist, a THAC0ist, a dialectical Gygaxian, and, consequently, an irreconcilable grognard.

My faith in the tablist future of Dungeons and Dragons and in constancy of THAC0 is not less ardent, indeed it is firmer today, than it was in the days of my youth.
 

Morrus

Well, that was fun
Staff member
Whether you decide that this is not "as complex as its reputation". It does literally require more operations.
And yet I stand by my assertion. It is not as complex (or, indeed, confusing) as it’s reputation.
 

Umbran

Mod Squad
Staff member
For forty-three years of my conscious life I have remained a revolutionist; for forty-two of them I have fought under the banner of THAC0. If I had to begin all over again I would of course try to avoid this or that mistake, but the main course of my life would remain unchanged.

I shall die an AD&D revolutionist, a THAC0ist, a dialectical Gygaxian, and, consequently, an irreconcilable grognard.

My faith in the tablist future of Dungeons and Dragons and in constancy of THAC0 is not less ardent, indeed it is firmer today, than it was in the days of my youth.
That's nice. Do you still use a rotary-dial phone, too? Drive a car that uses leaded gasoline? Listen to a lot of The Captain and Tennille? :p
 

lowkey13

I'm sorry, Dave. I'm afraid I can't do that.
Listen to a lot of The Captain and Tennille? :p
Puh-leeze.

Captain and Tennille?

You're drowning in the past, Umbran. But I've got your life vest right here: it's called yacht rock, and it's gonna be around forever.

That's right. McDonald. Loggins. Maybe a little of the Steely Dan, if you need to cut your smooth music with some acerbic commentary.

Smooth grooves- accept no substitute.
 

Umbran

Mod Squad
Staff member
And yet I stand by my assertion. It is not as complex (or, indeed, confusing) as it’s reputation.
Standing by un-measurable assertions is easy. It still looks like standing by your 1974 Ford Pinto* as a great car. :p




*Which had a reputation for blowing up if it got rear-ended
 
So instead of adding a number to your d20, you simply deduct a number from your THAC0. Same maths, just minus instead of plus.
There's your problem right there.

Subtraction is harder than addition. Lower things being better is the opposite to convention. THAC0's bad rep was well earned.

In 2E I replaced it with a system where armour classes started at 10 and went up and you rolled a d20, added modifiers, and tried to get equal to or greater than the target's armour class.
 

Gradine

Polymorphed Self
Moreso than the maths, which as many people have pointed out (and is relevant, by the by) is a tad more complex, the reason why BAB (and especially Proficiency Bonus) is much simpler is because the numbers are right there in your class/general level up descriptions.

As opposed to figuring out your THAC0, which is buried in an entirely different part of the book from character creation, on yet another table that has it's own sort of bonkers idea of steady progression (the Priest v. Rogue progression being particularly silly).

And that's not even going into 2e's "Weapon Type vs. Armor Modifiers" table.
 

Morrus

Well, that was fun
Staff member
But the thing I’m not clear on.... which is harder, addition or subtraction? Could somebody please just tell me!
 

DEFCON 1

Legend
See, the reputation I've always heard bandied about regarding THAC0 wasn't that it was "really complex"... but rather once 3E introduced ascending ACs its reputation was "My god, THAC0 was just STUPID. Why the hell did they ever do it that way in the first place?" :)

And this is why I have absolutely no need to ever play any version of D&D prior to 3E again. Because yes, THAC0 *is* just plain stupid and I have better things to do with my time. Hell... even when I play the original Baldur's Gates on occasion I have to bite my tongue, and the COMPUTER IS DOING THE WORK FOR ME!
 

lowkey13

I'm sorry, Dave. I'm afraid I can't do that.
See, the reputation I've always heard bandied about regarding THAC0 wasn't that it was "really complex"... but rather once 3E introduced ascending ACs its reputation was "My god, THAC0 was just STUPID. Why the hell did they ever do it that way in the first place?" :)
Y KANT R KIDZ DO MATHZ?

Fact: In 2014, 5e was released with its ... new math.

Also Fact: in 2015, for the first time in 25 years, math scores for 8th and 12th graders went down in the United States.


UNDENIABLE CONCLUSION:

Bring back THAC0.
 

GreyLord

Adventurer
But the thing I’m not clear on.... which is harder, addition or subtraction? Could somebody please just tell me!
Similar to which is harder, multiplication or addition?

For one who has learned elementary math, they can probably multiply 2x2 as easily as they could add 2+2. They could do an exam of 100 questions of easy addition (3+4, 7+2...etc) as quickly as they could multiplication (4x8, 3x6).

However, for some multiplication will always feel harder than addition.

The same probably also applies to subtraction.

Someone even did a science project or two showing this!!!

Not that any of it should be a problem for those who were the game's intended audience, anymore than figuring out whether you had an attack of opportunity or not.

But, I do know several that never figured out how THAC0 worked (I was the DM normally, so the burden would fall on me anyways) and had gotten their university degrees!

(and the same also applies to attacks of opportunities, always was asked whether they or something else were going to get one).
 

Sacrosanct

Legend
Standing by un-measurable assertions is easy. It still looks like standing by your 1974 Ford Pinto* as a great car. :p




*Which had a reputation for blowing up if it got rear-ended
If you're gonna use an analogy, use a correct one. D&D was one of the best RPGs back then, so you have to use a good car, not the worst. It would be like saying do I stand by my '68 Camaro. And you're darn right I do. I would fix everything myself, and it never broke down. My 17 Accord is always having wonky computer issues.
 

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