I've never understood the hatred some old school players have for ascending armor class any more than I understood the hatred some non-old school players have for descending armor class and/or THAC0. Ascending AC, descending AC with hit tables or descending AC with THAC0 are mathematically equivalent. That is, they all give exactly the same chance to hit for a given class, level, and target's armor class.
I saw all of these methods (and others) used back in the 1970s and early 1980s via house rules. However, I sometimes have trouble convincing people that ascending AC and attack bonuses were ever used back in the days when "old school" was the only school in town. Yesterday I was going through some old RPG magazines and I happened to look at the second part of a variant D&D combat article by John T. Sapienza, Jr. in Different Worlds #7 (the April/May 1980 issue). The first part of the article in the previous issue had tried to regularize the combat charts by using 1D100 instead of 1D20 for attack rolls, as it would allow fighters to improve their attack roll every level -- yet another example of the many different systems different campaigns used.
The second part closed by trying modify the d20 tables to provide at least some of the benefits of the previous issue's D100 system for those who wanted to continue to roll D20s in combat. The article provides such as system then goes on to say:
In fact, under this system it is possible to eliminate the Armor Class number system entirely. You would refer to your armor by its Armor Number: Clothing 10, Padding 11, Leather 12, Cuirboilli 13, Chainmail 14....
Do those Armor Numbers look familiar? They should as they are the same numbers used for Armor Class in the 3.x ascending AC system. Hits were determined by rolling a D20 and added one's Combat Class number to the roll and comparing it to the Armor Number, if the modified number rolled was greater than or equal to the target's Armor Number, the attack resulted in a hit. This "Combat Class number" and the Base Attack Bonus of 3.x are simply two different names for the same thing.
Sapienza even pointed out that this system was...
...a more rational system, since its numbers are directly related to combat function, and its pluses and minuses are actually added or subtracted (respectively) to or from the Armor Number, unlike the Armor Class system (in which a plus is actually subtracted from the Armor Class number, and a minus is actually added to the Armor Class number).
There you have it. Whether you like ascending AC or hate it, ascending AC really isn't a 3.x invention given that the basic system was printed in an article in a professional RPG publication in 1980. The point of this rant isn't that ascending AC is old school so old school players should not object to using it, but that there really was a huge variety in variant D&D rules in the first ten years or so of play and that claiming that ascending AC, spell points, or whatever else you do not personally like would have been considered badwrongfun/"not really D&D" by most D&D players back then simply is not true. Very little was considered "not really D&D" by most players at the time. Trying to claim otherwise is just as much revisionist history as 4e players trying to claim that OD&D combat was fought on grids with minis by most players.
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