Attacking Matrix and THAC0

[Deleted]

Using the tables as presented in M&M is too slow for me. I always like the THAC0 idea, so I did the conversion. Here are the values for the Fighting-Men:

Level	THAC0
1-3	19
4-6	17
7-9	14
10-12	12
13-15	10
16 & more	7

How to use it? It is simple: roll a d20 and subtract the result from the THAC0 value to know which Armor Class gets hit.

I.E. a Hero wants to hit an Orc. The Hero rolls a 13 so he hits AC 4 (THAC0 17 - roll 13 = AC 4), which is enough to hit an Orc (AC 6).

In my games, the players don't know the THAC0 value and the target AC. They just roll the dice and tell me what weapon are using, I do the maths quickly and tells them if is a hit or not.

Any comments?

[Porphyre]

And for those who find addition easier than substraction
1d20 + Armor Class > or = THAC0 is a Hit.

[Deleted]

That's right, Porphyre! Do you use THAC0 in your games?

[Zenopus]

As a player I find it even faster to just have my entire natural 'row' written on my character sheet: 19 18 17 16 15 14 etc.
Roll my d20, add any bonuses and tell the DM I hit AC9 or AC4 or AC0 etc.

[waysoftheearth]

THAC0 and THAC0-like methods certainly do work and are often more familiar to players coming from later editions of the game. That in itself may be a strong case, depending on the players, but I've tried THAC0, BAB, and the Target 20 method and found them all to be "more work" than the original tables. Even the simplest arithmetic is mental load compared to just knowing what you need to roll; applied across hundreds of rolls I've found it can genuinely slow play.

Over time I've also formed the impression that the various other methods lack the "old school charm" of the original attack matrices. That might not matter, but if we want to play OD&D, then wouldn't we want the whole OD&D experience?

Another consideration for THAC0 might be that OD&D covers ACs in the range 9 to 2; there is no AC 0 in the 3LBBs.

I'm not anti-THAC0 (or the other methods)--just reminding folks that there's also merit in the original method

[Porphyre]

Jan 10, 2015 15:46:38 GMT -6 @mmoreno80 said:

That's right, Porphyre! Do you use THAC0 in your games?

As a DM , I didn't. I grew up with the Metzer basic , so I was used with the written chart on the Characters' sheets.

But I have been involved, as a player, in some games that used it.
I find it rather convinient for on-line play-by-post games, as you don't always have your manuals , and your character "sheet" is just one post. 

My main problem with THAC0 is that some people use the unmodified THAC0 (the one you gave ), others use a modified THAC0 (using Stats and Magic modifiers), so you must be extra acreful when you start the game to define what mens the THAC0 on the Character Shhet 

(Of course, you still can write down the "normal" THAC0, then the "Modified" THAC0, but I think that would undermine the whole point of THAC0 i-e: having just one value for reference). 

[waysoftheearth]

"Don't ask me what you need to hit. Just roll the die and I will let you know!"
- Dave Arneson

See also: Do you tell players what they need to hit?

[Porphyre]

THAC0 use is still totally compatible with the "Just roll the dice" philosophy.

[Finarvyn]

I've never liked THAC0. It's just a personal preference. I rebuilt the combat charts into bonuses years ago (not as well as I have it today; I learned a few things from looking at 3E) because I like the idea that good armor should have a high value.

Having said all that, I have some AD&D friends who swear by THAC0 and say it's the best system ever. Others like Gronan have stated often that they prefer the feel of a combat matrix over equations. Lots of ways to do it, lots of ways to do it well.

Whichever system makes the most sense to you -- use it.

[snorri]

Jan 10, 2015 12:45:33 GMT -6 Porphyre said:

And for those who find addition easier than substraction
1d20 + Armor Class > or = THAC0 is a Hit.

The same

[skars]

Yeah these are all fine ways to do it, but I haven't looked back from ascending AC since 2000. It's just simpler, no need for extra tables or conversions. I play plenty of wargames and for me CRTs and TECs are commonplace. But for my kids or non-gamer friends that dabble, it's way easier to grok. When I play the classics I tend to prefer just sticking with the chart as opposed to introducing any additional arithmetic like thAC0.

[funkaoshi]

Here are all the ascending AC numbers, assuming a base ascending AC of 10.

[makofan]

THAC0 is an awesome shorthand for a DM to plunk in his reference table when he is managing a roster of PC's

I see Conan has THAC0 of 14. When he meets a monster AC 5 I know he needs (14-5) a 9 to hit it

[Stormcrow]

Conan has 8 HD. When he meets a monster AC 5 I know I can look at the table and not do any math at all.

[Deleted]

When playing OD&D, it's best just to use the number of hit dice as an attack bonus along with ascending AC.

[Porphyre]

Jan 13, 2015 10:12:43 GMT -6 @hedgehobbit said:

When playing OD&D, it's best just to use the number of hit dice as an attack bonus along with ascending AC.

Or even descending AC when using target 20. 

THAC0, Target20, etc are great tools if you're playing some kind of "bookless" game, for instance: a play by post online game on a forum, if you're connecting ten minutes a day and don't always have access to your manuals at the very moment you can be online.

Otherwise, I suppose the main thing is the familiarity with the system. Even if I'm not that "math-dumb", I didn't grew up with THAC0 and its use always needs some effort to me. 

Same thing with ascending Armor Class: as logical and simple that it can be, I'm used with the descending AC and using AAC is the same thing for me that using the metric system for an Anglo-saxon. 
If you say "Chainmail", I answer "AC 5!" , plate: "AC 3!" But if you say "AC 15 ", I'll be all : "Mmmmh, wait... What's that? Oh, right, it's chainmail!"

[snorri]

Jan 13, 2015 10:41:44 GMT -6 Porphyre said:

Same thing with ascending Armor Class: as logical and simple that it can be, I'm used with the descending AC and using AAC is the same thing for me that using the metric system for an Anglo-saxon. 
If you say "Chainmail", I answer "AC 5!" , plate: "AC 3!" But if you say "AC 15 ", I'll be all : "Mmmmh, wait... What's that? Oh, right, it's chainmail!"

I like the parralel The same or me.