Armor check penalty of mithral armors

[Gray Eminence]

The rules say that mithral armor has an armor check penalty 3 points less than normal armor of the same type. A paragraph later it also states that all armor and weapons made of mithral are automatically masterwork items.

It is not clear - at least to our group - if a mithral armor has an armor check penalty that is 3 (as it already includes the 1 point for being masterwork)or 4 (3 for being mitral, 1 for being masterwork) points better than a regular armor?

[northbrb]

i cant quote any line of text but i would say that the -3 check penalty includes the -1 for masterwork.

[Majuba]

It's 3 better, not 4. You can check this with some example items in the magic items chapter (elven chain, mithral full plate).

The reason it calls out mithral (and all the other materials) as "automatically masterwork" is threefold: (1) so that you don't get a 'masterwork' version of mithril items; (2) so you know you can enchant them (since masterwork is required); and (3) so weapons get +1 enhancement bonus to hit.

[LazarX]

Gray Eminence wrote:

The rules say that mithral armor has an armor check penalty 3 points less than normal armor of the same type. A paragraph later it also states that all armor and weapons made of mithral are automatically masterwork items.

It is not clear - at least to our group - if a mithral armor has an armor check penalty that is 3 (as it already includes the 1 point for being masterwork)or 4 (3 for being mitral, 1 for being masterwork) points better than a regular armor?

That line of text means that you can't say that you've made masterwork mithral armor with a total of -4 off of the penalty. Mithral armor is by it's nature as masterwork as it can get. In other words there is no such thing as nonmasterwork mithral armor.

[Charender]

Chainmail is a -5 armor check penalty.

SRD wrote:

Elven Chainmail

Aura no aura (nonmagical); CL —

Slot armor; Price 5,150 gp; Weight 20 lbs.

DESCRIPTION

This extremely light chainmail is made of very fine mithral links. This armor is treated, in all ways, like light armor, including when determining proficiency. The armor has an arcane spell failure chance of 20%, a maximum Dexterity bonus of +4, and an armor check penalty of –2.

I would say the +3 bonus includes the MW bonus.