Combat/To-Hit Matrix

[jaz0nj4ckal]

I only saw a copy of AD&D 1^st edition at one time; however, I do not own a copy. But what stood out to me, was the Combat/To Hit Matrix. How was this matrix developed or created? Was there a pattern or were the bonuses/penalties randomly generated? In addition, if I remember correctly – different weapons had better or worst chances hitting types of armor or AC.

Thanks
JJ

 

[TerraDave]

3Es bab was modeled on it.

Fighters basically increased their chance of hitting a particular AC by 1 each level, to hit AC 5 with a 15 or higher, then 14, or higher. etc. Other classes had slower progressions.

It required looking at the table (though players can also make a row on their char sheet showing what AC they hit with a result) but helped handle the low AC is good AC issue of pre 3E and simplified the math...no BAB to add and usually other hit modifiers where small, except maybe for higher level fighters.

 

[Blackbrrd]

3Es bab was modeled on it.

Fighters basically increased their chance of hitting a particular AC by 1 each level, to hit AC 5 with a 15 or higher, then 14, or higher. etc. Other classes had slower progressions.

It required looking at the table (though players can also make a row on their char sheet showing what AC they hit with a result) but helped handle the low AC is good AC issue of pre 3E and simplified the math...no BAB to add and usually other hit modifiers where small, except maybe for higher level fighters.

You don't have to look at a table, you just subtract your dice roll from THAC0 and tell the result. For example: d20 roll of 13 with a THACO of 15 gives 15-13 = 2. In other words, you hit AC 2.

The fighter had 1/1 progression (one lower THAC0 per level), the cleric had 3/2 progression (three lower THACO per 2 levels), The wizard had 1/2 progression, and so on.

 

[the Jester]

The fighter had 1/1 progression (one lower THAC0 per level), the cleric had 3/2 progression (three lower THACO per 2 levels), The wizard had 1/2 progression, and so on.

Those were the 2e values, which varied from the 1e ones. For one thing, the 1e fighter's attack values increased by 2 every other level in 1e, with a one-line option for the 1 per 1 mentioned only in passing in the DMG. IIRC rogues in 1e only improved about every 4 levels.

The other major difference was that the matrices had 6 20s in a row before the "DC" jumped to 21. IIRC everything after the first 20 required a natural 20 to hit.

 

[billd91]

Those were the 2e values, which varied from the 1e ones. For one thing, the 1e fighter's attack values increased by 2 every other level in 1e, with a one-line option for the 1 per 1 mentioned only in passing in the DMG. IIRC rogues in 1e only improved about every 4 levels.

The other major difference was that the matrices had 6 20s in a row before the "DC" jumped to 21. IIRC everything after the first 20 required a natural 20 to hit.

Yup, those matrices were more complex than THAC0. That's something a lot of people forget.

As far as the other modifiers, like weapon vs armor type, there's definitely a method behind the madness. I'm not sure exactly what the process was but the modifiers were designed to add a touch of reality to the game - by making some reasoned guesses about how effective a particular weapon would be against a particular type of armor - and modeling that in AD&D combat. Those tables were pretty cumbersome, though, so game play was usually hurt a bit by their use.

 

[Imperialus]

Yeah, the weapon vs AC table was intended to further differenciate the weapons. For example, a polarm like a Bec de Corbin was designed quite specifically to crack plate armour so it actually had a bonus to hit lower AC's. Some blunt weapons like maces and the like had bonus' against mid range AC's to simulate their effectiveness against flexable armour like chainmail.

 

[TerraDave]

Here is an example from OSRIC

You don't have to look at a table, you just subtract your dice roll from THAC0 and tell the result. For example: d20 roll of 13 with a THACO of 15 gives 15-13 = 2. In other words, you hit AC 2.

The fighter had 1/1 progression (one lower THAC0 per level), the cleric had 3/2 progression (three lower THACO per 2 levels), The wizard had 1/2 progression, and so on.

Thats THACO alright.

(for those lucky enough not to know, this was the default method in 2E, after being introduced in some latter 1E products.)

Where the table removes math, this puts it back in (and subtraction, which many people are slow with). But no table, sure.

 

[ExploderWizard]

Most adjustments to the "to hit" roll were applied to the target's AC instead of the die roll. This effect combined with the repeated 20 on the matrix makes a difference when dealing with the tougher AC values.

 

[howandwhy99]

Most adjustments to the "to hit" roll were applied to the target's AC instead of the die roll. This effect combined with the repeated 20 on the matrix makes a difference when dealing with the tougher AC values.

Yeah, I agree with EW. Typically a magical sword "+'s" altered a target's AC, while a magical chainmail "+'s" changed a To Hit die result. This widened the range of effectiveness players could explore within the d20 range, while leaving the average at a balanced 50%

Since the linear d20 roll results represented a curvilinear (parabola) of the games core design there were no rolls above 20 or below 1. Those were reaching to infinity constants. What we've done is reroll 20s and 1s when the odds are so low that 5% significance isn't detailed enough. Effectively the shifts above 20 and below 1 are within those gaps, so bonuses are still weighted in the game by logarithmic increase, not additive 5% chunks like in d20. (of course the early version also limits levels to half the d20, 10, for easy play)

Armor vs Weapon tables really allow for fine tuning of weapon designs and armor designs. Not only are we talking about a structural density for leather, chainmail, plate armors and the point/edge/blunt and materials of weapons striking them, but chain as weave, points as hooks, and other more edge case effects.

 

[Yora]

It's actually very easy to convert both THAC0 values and the to hit matrix to Base Attack Bonus.
Never understood why only so very few retroclones do it. (Maybe to use AD&D monster manunals without converting AC?)