Talk:THAC0/@comment-92.249.209.129-20180703152903

The real reason why this system is horrible is that its internal notation is all messed up. If you have a THAC0 bonus of +1 because your strenght is 17, it means your actual THAC0 at level one will be 19. Your 1+ bonus has to be substracted. However, if you look at other things, like dexterity defensive adjustment, it works differently. If your dex is 17, you'll get a -2 modifier, which means if your AC is 5 and there's an attack that's dodgeable and you can move, your AC against that attack is actually 3, so you simply substract it.

At this point, people would think, you just have to substract all the time, but no, because if you look at the damage modifiers, 1+ damage is really just added to the normal damage value. Then, you can look at saving throws, where you have to roll equal to or more than the target number. So if your saving throw versus X is 10 and you get a bonus of -2, you have to substract it, and you have to throw 8 or more than the target number, which makes sense, since your bonus should make it easier for you to succeed in the saving throw, therefore you substract it,