Why THAC0 Rocks

[Raven Crowking]

I guess I really am a genius. I never found THAC0 confusing in the slightest, even as a child.

Maybe you guys just don't do subtraction enough. I'm sure you could get better with practice.

Indeed.

I prefer positive AC (although not exactly BAB), and it is what I am using in RCFG. I prefer positive AC because it is easier to explain, initially, although negative AC includes forcibly within it the obvious "tipping point" for armour where the DM should begin to exercise some caution. Positive AC can lead to serious numbers inflation, if not checked, simply because the inflation is less obvious than in negative AC.

Also, I have never met anyone in real life who was unable to grasp either THAC0 or BAB.


RC

 

[vagabundo]

THAC0 was always a barrier to my more casual players, they would look on in puzzlement as I figured it out for them. It definitely didn't speed up my games, it was a hindrance.

I think the measure of it was how quickly I forgot how to do it after I switched to BAB.

And most people can add quicker than they can subtract in my experience.

 

[Remathilis]

Also, I have never met anyone in real life who was unable to grasp either THAC0 or BAB.

FWIW, the only people I ever met who never got Thac0/Downward AC were typically casuals (girlfriends, interested siblings) who barely got the basics of what an RPG is, let alone its mechanics. While 3e tended to overwhelm in other areas, I don't think I met too many casuals who didn't get "add roll X to bonus Y and tell the DM" while plenty lost it at "what am I subtracting from what again?"

For anyone who actually stuck with and learned the game though, Thac0 could be grasped.

 

[Obryn]

Would now be a good time to point out that THAC0 doesn't even work in by-the-book 1e?

Those repeating 20's will catch you up every time.

-O

 

[Reynard]

Never m ind THAC0 -- just use the combat matrices. There's a good solid reason why those tables weren't in the PHB in 1E -- it's the DM's job to adjudicate, which includes combat. When a character makes an attack, the player's job is to give the DM a total ("I rolled a 17!") and the DM's job to relate what happens ("Your sword stabs for his throat but he raises his shield just in time and you leave him with merely a nasty cut on the cheek.") I believe it was B/X that actually had the DM rolling for damage (though the player rolling for damage isn't a bad thing -- but i would suggest doing so simultaneously with the attack roll).

The same goes for saving throws in the "old school". The DM knows what save is required and what counts as a successful save. All the player has to do is roll the die and tell the DM what he got. The DM informs the player that he was turned to stone, dropped off the ledge and shattered into 1000 pieces.

And before anyone screams control-freak DM, there's a real, player benefit reason to do this: every time the player has to look at his character sheet and add modifiers or look at the battleboard and count squares, that player is pulled out of the game. He's no longer thinking "Rath is pissed! That hobgoblin is going down!" He's instead thinking "If I move over here and get a flanking bonus, then I can power attack for 4 points and still have a 75% chance of hitting his AC." While the latter is wrong or bad, IMO it is less fun.

 

[Obryn]

FWIW, I adapted a pseudo-BAB for my 1e game. Mathematically, it works identically to the tables, but it front-loads the math. I wanted to run as close to BtB as possible, but found that applying combat modifiers to the target's AC (rather than to the die roll itself) broke my brains.

(1a) For Fighters/Rangers/Paladins, take (Level-1).
(1b) For all other classes, look at the AC 10 row on the chart and find 10 minus this number. (So, for a wizard, this would be -1 at 1st level.)

(2) Add all other bonuses from strength/dex, magic, and specialization. This gives your Combat Bonus.

(3) In combat, roll a d20, add your Combat Bonus. A roll of 20 counts as a 25, to replicate the repeating 20's on the tables.

(4) Behind the screen, I quickly add the monster's AC to this number. If it equals or exceeds 20, it's a hit!

Monsters are even easier at low levels. I just add their hit dice to the d20 roll, rounding up a hit die if they have from +1 to +3 extra HPs. (And more dice if they have more.)

Then, I can put away the tables while preserving the combat math of 1e.

-O

 

[Filcher]

I hope this thread lives for a long, long time ... 3.5 and 4E fans united!

So tell me more about this Thahcoe.

 

[Sir Brennen]

I think the argument isn't that THAC0 and BAB calculations are mathematically equivalent isn't really the point. It's the basic premise, the starting parameters, of THAC0 that initiates confusion in some players. Start at 10 and decrease my AC value as it gets better? And I can go negative? Whaaa?

I'm sure this has its roots in some wargame resolution table. But just the idea that "increasing the amount of protection I'm wearing" = "an increase in the value of the number that represents the amount of protection I'm wearing" is a straight-forward, intuitive approach. For THAC0, many people get stuck on "why does it work that way?"

And boiling down the comparison to THAC0 vs. BAB ignores the fact that these are both integral parts of their respective game systems, and additional confusion was caused by the way THAC0 worked with respect to the rest of the system. I add my Strength bonus and magic weapon bonus to my attack roll but subtract my Dex bonus and magic armor bonus from AC. So a bonus is a subtraction... except when it's not? You need me to make a Str check? Okay. 20! Awesome! What? I blew it? I thought 20 was the best thing you could roll?

With 3E and beyond, there's no need to mentally switch gears (or dice) when going from Saving Throws to Attacks to Hide in Shadows to Attribute Checks. This fact means that overall, 3E should play faster. However, in practice, I think that it then occasionally loses some momentum due to the many additional bonus/penalty/options which crop up in play that didn't in previous editions, which players and DM alike need to track.

 

[Mallus]

He's no longer thinking "Rath is pissed! That hobgoblin is going down!" He's instead thinking "If I move over here and get a flanking bonus, then I can power attack for 4 points and still have a 75% chance of hitting his AC."

The people I game with have no trouble thinking both thing simultaneously, or at least, can effortlessly switch between player and character.

This has the added benefit of allowing the DM to be completely transparent about the mechanics ("It's REF defense is 19") and thus off-loading some of the crunch-work to the players.

Oh, and good riddance to THAC0!

 

[Reynard]

The people I game with have no trouble thinking both thing simultaneously, or at least, can effortlessly switch between player and character.

I'm doubtful, but I'll take your word for it.

This has the added benefit of allowing the DM to be completely transparent about the mechanics ("It's REF defense is 19") and thus off-loading some of the crunch-work to the players.

I am not sure this is a benefit -- or, rather, I am not sure the benefits outweigh the costs.