THAC0 Table Inflation

Through the 1st, 2nd, and 3rd editions of AD&D and then D&D, PC THAC0s experienced a sort of inflation, making their lives much easier in their quests for XP and treasure (and making DMs' quests to destroy them a bit more difficult (but not that much)).

In 1st edition, THAC0 advancement was irregular and ultimately limited (i.e. there was a value "cap"). PCs in general improved their THAC0s in increments of more than 1, but not at every level (i.e., fighters went from THAC0 20 to 18 at level 3), to balance similar gains of other classes (for example, clerics went from THAC0 20 to 18 at level 4). In general, fighters, rangers, and paladins were the best at combat, while clerics, druids, and monks were good as well; thieves and wizards were on the low end, but at higher levels, they received larger-than-normal THAC0 improvements (i.e. magic-users went from THAC0 19 to 16 at level 11, while thieves got the same at level 9). On the other hand, monsters had quite good THAC0s at lower HD (a 2 HD monster had a THAC0 of 16), but slowed in advancement as they got stronger, with a maximum THAC0 of 7 (at 16 HD).

In 2nd edition, THAC0 advancement was smoothed out and made regular; in addition, THAC0 limits were removed (except for monsters). Warriors thus now could look forward to a better THAC0 (by 1) at each level advancement, allowing them to be an edge (and some) ahead of their non-warrior peers. Thieves' low-level THAC0 improved a good deal as well, but at advanced levels they reached a similar level to their 1st edition counterparts; wizards THAC0s were similarly improved at low levels, but at higher levels, they became worse. Weak monsters had worse THAC0 as well, while stronger monster had slightly better THAC0, with a new maximum THAC0 of 5 (at 15 HD) (although PCs were no longer restricted by maximum THAC0s, monsters still were).

In 3rd edition, the regularity of 2nd edition was retained, expanding to include monsters as well, who simply used the same table as fighters (or other classes). Fighters started out with a better THAC0 by 1 at 1st level (until now, they started out with THAC0 20 like everyone else), while the other classes received boosts of their own. Priests and rogues (the new name for thieves) now were vastly improved in combat (thieves in particular - now they became equal to priests on the battlefield), while wizards became much better at combat as well - roughly about the level of thieves in 2nd edition.

Actual THAC0 figures to view and compare are as follows (values are for level 1, 2, 3, etc.):

Fighter:
1e: 20 20 18 18 16 16 14 14 12 12 10 10 8 8 6 6 4* 4 4 4
2e: 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
3e: 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Cleric:
1e: 20 20 20 18 18 18 16 16 16 14 14 14 12 12 12 10 10 10 9* 9
2e: 20 20 20 18 18 18 16 16 16 14 14 14 12 12 12 10 10 10 8 8
3e: 20 19 18 17 17 16 15 14 14 13 12 11 11 10 9 8 8 7 6 5

Thief (Rogue):
1e: 20 20 20 20 19 19 19 19 16 16 16 16 14 14 14 14 12 12 12 12 10*
2e: 20 20 19 19 18 18 17 17 16 16 15 15 14 14 13 13 12 12 11 11 10
3e: 20 19 18 17 17 16 15 14 14 13 12 11 11 10 9 8 8 7 6 5

Magic-user (Wizard):
1e: 20 20 20 20 20 19 19 19 19 19 16 16 16 16 16 13 13 13 13 13 11*
2e: 20 20 20 19 19 19 18 18 18 17 17 17 16 16 16 15 15 15 14 14
3e: 20 19 19 18 18 17 17 16 16 15 15 14 14 13 13 12 12 11 11 10

Monsters:
1e: 19 16 16 15 15 13 13 12 12 10 10 9 9 8 8 7* 7 7 7 7
2e: 19 19 17 17 15 15 13 13 11 11 9 9 7 7 5* 5 5 5 5 5
3e: 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

*Maximum values

In general, 1st edition was the hardest to remember but the most interesting and the most balanced. In 1st edition, low-level humans and demi-humans were no match for grubby goblins, orcs, or lizard men; however, at high levels, humans and demi-humans were heroes, quite a bit more skilled than the monsters they came to dominate. Our 1st edition PCs also had epiphanies - usually at "name level." Maximum THAC0s also helped to retain game balance, with the idea that there is a limit to possible skill.

2nd edition was clearly easier to remember, but game balance was a bit worse and at high levels, PCs had it too easy. At least, clerics and druids should have been given incremental increases as well (i.e., 20 20 19 18 instead of 20 20 20 18) so that they did not have to be useless for so long.

3rd edition was even easier to remember (although multi-classing made things complicated anyway), but it seems that the non-combat classes became too good at combat.