Jul31
on July 31, 2018
E-Diction War
THAC0 or “to hit armour class 0” was the kludge way 2nd Edition got around having to have charts and tables determine if an attack roll was successful, using some reverse addition and funky math. So if you had a THAC0 of 11 and rolled a “13” with a +2 bonus, you’d hit AC -5, which was better than AC 0 or AC 5. But if you had a THAC0 of 18 and rolled the same, you’d only have hit AC 3.
While not *that* much harder in terms of math, it was noticeably slower at the table. You had to total up your bonuses and then do the math to figure out what AC you would have hit to relay that info to your DM. While in 3e and beyond, just totalling up your bonuses was all the required math. (Although, the bonuses tended to get a lot higher.)
I hear you on the “THA-CO” thing. ;)
It is universally hated! You know its hated when old-timers rather use the BAB (base attack bonus) to-hit bonuses! How I know this? I have read a TON of OSR (old-school revival/rules, aka “retro-clones”) rulesets, and while there are hardcore purists who only ever use to-hit tables, most of them prefer the quicker BAB method.
Although, much of the popularity with the old-school crowd is due to the simplicity and open-source nature of Swords & Wizardry, with a lot of people publishing their own core rules, source-books and modules around it. To remain flexible, it lists to-hit tables and THAC0s (for monsters) alongside BABs, along with listing both regressive and progressive AC scores, but a lot of independent S&W-based rulesets outright drop THAC0 scores and to-hit tables in favor of BABs and progressive AC scores. You should see how S&W handles saving throws!