Thondor
I run Compose Dream Games RPG Marketplace
There has always been a rhetoric on these boards that discredits THAC0 (To Hit Armour Class 0) as being by far inferior to BAB (Base Attack Bonus). Posters state this as a matter of course, saying things like the adjustement to BAB (from THAC0) was so inherently logical that it is stunning that it didn't happen earlier.
I will attempt to explain here why THAC0 was created, how it works and why it is in fact simpler, speeds up play, and better then BAB.
Able to write a history of the evolution of THAC0 I am not. I know that in the 1e DMG both combat tables and THAC0 were used. And that BAB began in 3rd edition.
1. With THAC0 you know wether you hit on a tie or not. (This is the same with the saving throw tables in 1e/2e etc by the way.) There is no inherent logic that tells you wether you hit on a tie with BAB, wether you make a save on a tie, wether you beat the DC of a skill cheque on a tie. (Yes it says this on p.62, p.134, in the 3.5 PHB. However these are in isolated places and are not inherent to the definition. As far as I can tell, it does not actually say wether or not saving thows win on a tie.) With THAC0 the name itself says it all. If you have a THAC0 of 17, you must roll a 17 to hit a Armor Class of 0.
2. Ease of Use. A character who had a BAB of +5 would have a THAC0 of 15. Compare
A 3e character with a BAB of +5 tries to hit a enemy with a AC 15. Player rolls a 7, (ummm 7 plus 5 is 12) hey DM I got a 12. DM you miss. Next round, Player rolls a 13, (umm 13 plus 5 is uh 18), hey DM I got a 18. You hit. Next round, player rolls a 8 (umm, 8 plus 5 is 13), hey DM I got a 13. DM you miss.
A pre-3e character with a THAC0 of 15 tries to hit an enemy with a AC 5.
Player rolls a 7. Player says "7", DM says "you miss". (The DM knows that no one around the table has a THAC0 better then 14.) Next round, Player rolls a 13, says 13 DM says you hit (DM knows that everybody around the table but the wizard has a THAC0 of at least 18.) Next round, player rolls a 8, "I rolled an 8", DM is distracted "What's your THAC0?" Player "15", Dm thinks (15 -5 = 10) "You miss."
Let me explain that a little better in a different way and we'll get to another one of my points:
3. THAC0 means you do one calculation per different AC of opponent.
Same example THAC0 15 character trying to hit AC 15. This DM doesn't mind letting the players know the opponents AC.
Another player has attacked the same creature already. The DM informed them the AC was 5. Before rolling the player thinks to himself 'My THAC0 is 15 - 5 AC= 10, I need to roll a 10 or better to hit, sweet 50% chance!' (actually its a 55% chance) Informed that he's next, the player rolls a 7 "7! darn I miss." DM "OK next person". Next round, Player rolls a 13, "Yes a 13, I hit". Next round, Player rolls a 8, "8! I think I miss, 15-5 yeah I miss."
compared to:
DM says alright the AC is 15. the player has a BAB of +5.
First round: Player rolls a 7. 7+5 =12. "I got a 12, I miss."
Second round: Player rolls a 13. 13+5 =18. "I got a 18, I hit."
Third round: Player rolls a 8. 8+5 =13. "I got a 13, I misss."
With THAC0 you figure out what number you need to roll on the die once. With BAB you roll the dice, add your modifier, and compare it to the target number . . . every single attack.
I have found that THAC0 leads to much, much, quicker combat. For some reason people have an inherent fear of substaction, and have difficulty overcoming the initial conceptualization of THAC0. Which is really quite simple.
THAC0 - opponents AC = number you need to roll on the dice.
the 'complicated example' that many state of a negative AC is really simple: Say an AC -2, THAC0 15.
15 - - 2= 15 +2= 17. not difficult.
I will attempt to explain here why THAC0 was created, how it works and why it is in fact simpler, speeds up play, and better then BAB.
Able to write a history of the evolution of THAC0 I am not. I know that in the 1e DMG both combat tables and THAC0 were used. And that BAB began in 3rd edition.
1. With THAC0 you know wether you hit on a tie or not. (This is the same with the saving throw tables in 1e/2e etc by the way.) There is no inherent logic that tells you wether you hit on a tie with BAB, wether you make a save on a tie, wether you beat the DC of a skill cheque on a tie. (Yes it says this on p.62, p.134, in the 3.5 PHB. However these are in isolated places and are not inherent to the definition. As far as I can tell, it does not actually say wether or not saving thows win on a tie.) With THAC0 the name itself says it all. If you have a THAC0 of 17, you must roll a 17 to hit a Armor Class of 0.
2. Ease of Use. A character who had a BAB of +5 would have a THAC0 of 15. Compare
A 3e character with a BAB of +5 tries to hit a enemy with a AC 15. Player rolls a 7, (ummm 7 plus 5 is 12) hey DM I got a 12. DM you miss. Next round, Player rolls a 13, (umm 13 plus 5 is uh 18), hey DM I got a 18. You hit. Next round, player rolls a 8 (umm, 8 plus 5 is 13), hey DM I got a 13. DM you miss.
A pre-3e character with a THAC0 of 15 tries to hit an enemy with a AC 5.
Player rolls a 7. Player says "7", DM says "you miss". (The DM knows that no one around the table has a THAC0 better then 14.) Next round, Player rolls a 13, says 13 DM says you hit (DM knows that everybody around the table but the wizard has a THAC0 of at least 18.) Next round, player rolls a 8, "I rolled an 8", DM is distracted "What's your THAC0?" Player "15", Dm thinks (15 -5 = 10) "You miss."
Let me explain that a little better in a different way and we'll get to another one of my points:
3. THAC0 means you do one calculation per different AC of opponent.
Same example THAC0 15 character trying to hit AC 15. This DM doesn't mind letting the players know the opponents AC.
Another player has attacked the same creature already. The DM informed them the AC was 5. Before rolling the player thinks to himself 'My THAC0 is 15 - 5 AC= 10, I need to roll a 10 or better to hit, sweet 50% chance!' (actually its a 55% chance) Informed that he's next, the player rolls a 7 "7! darn I miss." DM "OK next person". Next round, Player rolls a 13, "Yes a 13, I hit". Next round, Player rolls a 8, "8! I think I miss, 15-5 yeah I miss."
compared to:
DM says alright the AC is 15. the player has a BAB of +5.
First round: Player rolls a 7. 7+5 =12. "I got a 12, I miss."
Second round: Player rolls a 13. 13+5 =18. "I got a 18, I hit."
Third round: Player rolls a 8. 8+5 =13. "I got a 13, I misss."
With THAC0 you figure out what number you need to roll on the die once. With BAB you roll the dice, add your modifier, and compare it to the target number . . . every single attack.
I have found that THAC0 leads to much, much, quicker combat. For some reason people have an inherent fear of substaction, and have difficulty overcoming the initial conceptualization of THAC0. Which is really quite simple.
THAC0 - opponents AC = number you need to roll on the dice.
the 'complicated example' that many state of a negative AC is really simple: Say an AC -2, THAC0 15.
15 - - 2= 15 +2= 17. not difficult.
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