The truth about THAC0

[Viktyr Gehrig]

For instance: How many 19s and 20s were there on the end of the attack table? How many 2's at the other end?

I'm fairly certain that the table had something like 3 19s before 20... Can anyone tell me if I'm wrong?

Before it was revised (I think in the second printing of the PHB, but I may be wrong), Fighters got 2 THAC0 per 2 levels, instead of 1 per level.

 

[Crothian]

I'm pretty sure that thaco was not all that there was to it.

For instance: How many 19s and 20s were there on the end of the attack table? How many 2's at the other end?

I'm fairly certain that the table had something like 3 19s before 20... Can anyone tell me if I'm wrong?

It does have 6 20's in it, yes. but not a lot of twos, in fact the numbers go negative. So, the forumalu just has the 20's rep[eated the six times and then goes on from there.

First level fighter nmeeds 20 to hit AC 0, and a 20 to hit AC -5, a 25 to hit -10

 

[Staffan]

Indeed.

2e:
Fighters reduce THAC0 by 1 per level.
Clerics reduce THAC0 by 3 per 4 levels.
Thieves reduce THAC0 by 1 per 2 levels.
Mages reduce THAC0 by 1 per 3 levels.

Actually, priests reduced THAC0 by 2 per 3 levels.

 

[Viktyr Gehrig]

You're probably right-- I couldn't remember whether it was 2/3 or 3/4. 2/3 makes more sense, though.

 

[whydirt]

THAC0 wasn't that bad, but I think the BAB system is A. more intuitive to new players B. more consistent with the rest of 3rd Edition's rules.

I think the part that was the most confusing wasn't THAC0 itself, but that Armor Class started at 10 and worked its way down to below 0. Now Armor Class is essentially just another Difficulty Class with a specific name kept from older editions.

 

[MerricB]

There were two issues:

The first was mathematical. People add much faster and more accurately than they subtract. When you have subtraction of negative numbers, things get hairy for the less mathematically competent amongst us.

For a fighter with a THAC0 of 14 to strike a monster of AC -2, the fighter had to roll a 16 or higher (14 - (-2) = 16).

I had someone in my old group who I had to explain how THAC0 worked every single session. This was a problem.

The second was due to inconsistency between whether rolling high was good (saves and attack rolls) or whether rolling low was good (attribute and proficiency checks).

Jonathan Tweet notes that the attribute/proficiency system (rolling low) also worked very badly for opposed checks... it ended up being who rolled higher without rolling higher than their skill! The unified d20+modifiers check of 3e fixed that problem very nicely.

Cheers!

 

[Jdvn1]

/me seconds the inconsistency arguement.

The d20 system is easier because the entire system is "meet or beat this number." You always know you want to roll high. Mechanically, the same, logically simpler.

 

[weasel fierce]

AD&D1 and classic D&D uses the "repeating 20".

AD&D 2nd edition didn't. The chart was even, throughout the advancement.


Also, as I illustrated, you dont need to subtract anything. Just add the armour class of the target to your roll, and score equal or higher than THAC0. Same mechanic as 3.x


Saving throws were rather arbitrary but they still are. Of course you find them in the same way. Look on a chart, write down the number.

 

[Caliban]

AD&D1 and classic D&D uses the "repeating 20".

AD&D 2nd edition didn't. The chart was even, throughout the advancement.


Also, as I illustrated, you dont need to subtract anything. Just add the armour class of the target to your roll, and score equal or higher than THAC0. Same mechanic as 3.x

Sure. It's not like they made a secret of that. It was talked about by the designers when 3.0 was first released.

Saving throws were rather arbitrary but they still are. Of course you find them in the same way. Look on a chart, write down the number.

Saving throws aren't arbitrary, they follow a simple formula: 1/2 your level +2 for "good" saves or 1/3 your level (round down) for "bad" saves.

I haven't looked on a chart for saves (unless I'm feeling lazy) for quite awhile.

 

[ThirdWizard]

Also, as I illustrated, you dont need to subtract anything. Just add the armour class of the target to your roll, and score equal or higher than THAC0. Same mechanic as 3.x

I think the PCs knowing the AC of their enemy is a pretty big assumption. That's definately not any information I ever handed out.