Tuesday, May 8, 2012


Growing up playing 2e, there was one way to determine whether you hit or not.  Take your THAC0, subtract the AC, adjust for modifiers, and compare to the roll.  If it was higher, you hit, if it was lower you missed.  Simple.  It was great, because it gave me a head start on working with negative numbers when I was in school (of course 2 minus -2 is four, duh how else will I hit the elder dragon?).  It numericized (not sure if that's a word but if it isn't it should be) the "To Hit" table from 1e, making it easier for DMs to create and put forth monsters on the fly, and was generally awesome, in my humble opinion.

I recently introduced a group of gamers to the concept, none of which had played 2e before.  They had played 4e, 3e and 1e, so they had very different ideas on how to do things.

We started playing, and the numbers they rattled off made absolutely no sense to me, I had to have them break it down.  Rather than subtracting the AC from the THAC0 and comparing the score to the roll, they were taking the roll, adding the AC and any modifiers, and comparing the total to the THAC0.  It took awhile for me to be able to wrap my head around it, but it does work, I suppose.

Which makes me wonder if there are other ways to do it...


  1. Back when I was running 2e, I wouldn't tell the players the AC of the monster until after the first round of combat. So they would subtract their roll from their THAC0 and tell me what AC they would be able to hit. Then I'd tell them if they should roll damage or not. This preserved some mystery as they tested the critter's combat skills.

    Before the second combat round I would say something like "it's pretty quick and has tough chitinous plates, so it's AC:2. So far, it's wounds seem minor".

    After that they would use (THAC0-AC) to see the target number they needed to hit before they even rolled. Modifiers were only added after the roll if the result wasn't obvious. This helped to speed combat because we could often skip over all the fiddly modifiers.

    It worked for us, and we liked it.

  2. Interesting, I like that. Coincidentally, I just picked up a copy of 2E's First Quest, a basic, introductory version of 2E, and they also use the THAC0 - die roll vs. AC method, so maybe I've been doing it wrong all these years?

  3. Actually, Stars Without Number does it this way- except instead of giving a class a steadily-descending THAC0, it just gives each class a steadily-increasing attack bonus and makes 20-or-better the target to hit. I preferred to avoid subtraction in the process, so I just made the whole routine additive.