Why THAC0 Rocks

[El Mahdi]

Six of one, half-dozen of the other.

It seems as if they're both just different paths to the same destination.

Different people like different views or modes of transportion, but they all end up at the same place. (However, personally I prefer BAB. To me, the BAB path seems to be a little less rocky.)

 

[GMforPowergamers]

10 years out of date here...but lets see how I do...


Ok I am a 3rd level fighter...I have a thac0 of 18...I have a +1/+3 str and weapon specilization +1/+2, and a +2 long sword....


I roll a 12 I add 4 (2 magic 1 str 1 training) and have a 16...I subtract my 18 thac0 and have 2...so I hit AC 2 then I would roll 1d8+7 for damage

we use to have adjusted thac0...so above I would write on the sheet
in the Thac0 box 18/14


Now adays I would have +X....lets say 3rd level fighter 16 str and weapon focus longsword...and a MW longsword
+8 1d8+3

Now I roll a 12 in eaither case I know I hit AC 20 or AC 2...the math is simple in play...but hard to explain, and not that simple to learn the old way...

 

[Thondor]

It takes more verbiage to explain why THACO is simpler and easier than it takes to explain BAB to begin with. That says to me that THACO is not, in fact, actually simpler and easier.

YMMV, of course.

Here's me explaining THAC0: the number you roll >= THAC0 - AC

Here's me explaining BAB: the number you roll + BAB => AC

it is in fact the exact same amount of words. Explaining why one is better then the other will of course take substantially more verbiage. No matter what side you take.

Which says to me that unfortunately your point is illogical. I do however value your imput, and would welcome further criticism.

 

[BryonD]

In your example what's A and what's B? I'll be plain with you and admit I don't know what your getting at.

Look at your own example.
THAC0 requires subtraction which requires keeping the numbers straight.
BAB is addition, the elementary level commutative property applies.

In your "easy" example you have jumped to the (rather poor) presumption that the AC is always known. Yet in the BAB example the DC is unknown and must be checked against each time. You are still requiring the BAB player to be intentionally dumb while giving the THAC0 example player a the presumption of knowledge and correct procedure.

You are basing the arguement 100% on this stacked deck presumption.

Again, THAC0 is easy. I'm not arguing with you there. But BAB is is every bit as easy AND it is more intuitive to 90%+ of people.

To me THAC0 is easier because the math is a constant, i.e. for one opponent and one attacker it is always the same.
eg: x (The only variable in either equation) is the number rolled on the dice.

Using THAC0: if x => THAC0 - AC it hits
Using BAB: if x + BAB => AC

So if a player wants to figuer out what they need to roll with BAB, they can. But they need to rearrange the equation in their head.
( x+BAB => AC
x + BAB - BAB => AC - BAB
x=> AC - BAB)
Which certainly isn't 'intuitive' and is actually exactly what THAC0 is. (S'mon basically said this above, far more eloquently then I have.)

The trick with THAC0 is figuring it out before the roll is made.

You are talking about addition and subtraction with numbers in the 1 to 30 range.
It ain't rocket science.

If you don't know AC then BAB is easier because you can tell the DM your total and he knows if you hit or not. If you don't know AC with THAC0 then you have to tell the DM your THAC0 and the roll. And you must keep the numbers straight.

If you do know the AC, then it is 2nd grade math to get the target roll number under either system. Perhaps THAC0 is easier for C- level 2nd graders. I'm not so sure though.

But if the getting a target number out of BAB is difficult for someone, then I probably just can not relate to their perception of the system.

But to virtually every gamer I've ever played with, BAB is THAC0 presented in the way that humans actually think.

 

[Thondor]

10 years out of date here...but lets see how I do...


Ok I am a 3rd level fighter...I have a thac0 of 18...I have a +1/+3 str and weapon specilization +1/+2, and a +2 long sword....


I roll a 12 I add 4 (2 magic 1 str 1 training) and have a 16...I subtract my 18 thac0 and have 2...so I hit AC 2 then I would roll 1d8+7 for damage

we use to have adjusted thac0...so above I would write on the sheet
in the Thac0 box 18/14


Now adays I would have +X....lets say 3rd level fighter 16 str and weapon focus longsword...and a MW longsword
+8 1d8+3

Now I roll a 12 in eaither case I know I hit AC 20 or AC 2...the math is simple in play...but hard to explain, and not that simple to learn the old way...

Well actually the way you did it is harder and is confusing, and actually wrong.
You Took the roll, add modifiers, then substracted THAC0 which actually results in a negative 2 not positive 2. and then you compared it to AC.

You don't compare your roll to AC. You compare your roll to THAC0 - AC. if your roll was that number or better you hit.

First of course you would already have include all the modifiers in your "long sword THAC0" just like you figure out for your "long sword Attack bonus" (Your right it is 14, just like its +8)

So you roll a 12, does that hit? 14-2 =12 so yes it does.

 

[Thondor]

Look at your own example.
THAC0 requires subtraction which requires keeping the numbers straight.
BAB is addition, the elementary level commutative property applies.

In your "easy" example you have jumped to the (rather poor) presumption that the AC is always known. Yet in the BAB example the DC is unknown and must be checked against each time. You are still requiring the BAB player to be intentionally dumb while giving the THAC0 example player a the presumption of knowledge and correct procedure.

You are basing the arguement 100% on this stacked deck presumption.

Actually I was extremely careful that in the example in number 2, neither player knows the AC. And in number 3, they both know the AC.

I did give the DM in the example number 2 (where AC was hidden) a small advantage over the player doing the addition. But that is because well the DM usually has some manner of advantage.

With THAC0 the DM decides if s/he wants to do the math (by hiding the AC) or wants the players to (By giving the AC). In all cases with BAB the Player does the math. Another advantage in my opinion.

 

[Thondor]

I do admit that understanding how THAC0 functions is slightly more difficult conceptually. However, it more then makes up for it in accelerating game play. It is a concept that is easily explained by doing it though.

Player: I don't get this THAC0 thing, why does AC go down?
DM: Both AC and THAC0 go down, lower is better. Your character has a THAC0 of 20 right
Player: Yeah
DM: Suppose you want to beat up and average bloke. He's not wearing any armour or particulary good at dodging, so his AC is 10.
Player: Um . . . OK . . .
DM: To know what you need to roll on this dice (holds up a d 20) in order to hit him, all you do is minus the AC from your THAC0
Player: oh, so 20 - 10, 10.
DM: Roll the dice
Player: It's a 12, so I guess I . .. hit.
DM: you hit, now you roll damage. Sometimes I won't tell you the AC, so you just tell me what you roll and I'll figure out if you hit.

Yeah it can be a little DM heavy. If you want it to be. Still remebering a few players THAC0 isn't that tough. And you can just ask. Most of the time it'll be obvious though. Hmm he rolled really high. hit. really low miss. You can do this with BAB to of course but it's harder.

One of the things that troubles me with BAB as a DM is that my players often say what they rolled and what they actually got (roll+BAB) which leads to confusion. Player " 17" DM "you missed", Player "what!? Last time I roll a 14 and hit!" DM "sigh, did you roll a 17 or get a 17?"
(note these players never played with THAC0 and should no better )


an aside
The mere fact that a DM can tell a player what they need to roll to hit, means it is much easier for those who have some difficulty with math ( in some cases because their Kids) to play.

 

[Freakohollik]

The only point in your argument that I find to be partly valid is when using THAC0, it is implied that players know the opponenets' ACs. You can get the same speed up from BaB if the DM decides to tell the players the AC values, and the players then figure out what they need to roll before they roll. The difference is that the THAC0 system almost required you to know the opponent AC, where as BaB system implied that the players should not know the opponents' AC.

 

[Remathilis]

Well actually the way you did it is harder and is confusing, and actually wrong.
You Took the roll, add modifiers, then subtracted THAC0 which actually results in a negative 2 not positive 2. and then you compared it to AC.

You don't compare your roll to AC. You compare your roll to THAC0 - AC. if your roll was that number or better you hit.

First of course you would already have include all the modifiers in your "long sword THAC0" just like you figure out for your "long sword Attack bonus" (Your right it is 14, just like its +8)

So you roll a 12, does that hit? 14-2 =12 so yes it does.

See that again assumes your DM has told you the target AC. As a DM, I rarely ever tell the AC of a foe (in any edition).

So if I roll my longsword attack (thac0 14) I know two parts of the equation, my roll and my thac0. I don't know my foe's AC. So my only option is Thac0 - roll = AC, not Thac0 - AC = roll.

 

[Ariosto]

Some prefer one expression, some the other, of what is fundamentally the same thing. Still others prefer starting with a table look-up to needing always to engage in arithmetic -- and 1st edition AD&Ders may appreciate the subtlety of repeating 20s.

In my experience, what actually seems to appeal most to players (if they want to be concerned with the mechanic at all, rather than leaving it to the DM) is a table on the character sheet. Class, level, proficiency, strength, magic, the peculiarities of a guisarme-voulge ... all can be figured in already. Just look up the relevant Armor Class, and beneath it is the number needed.