[Amorphous]

Originally Posted by Peter Ebbesen

So is extra defense from Quickness +3, which also gets its own line, or Prophet +2, Experience + X, and several other (all?) defense modifiers that get added separately and aren't labeled +defence on equipment, and the sum of all those are listed as the "Current Defence and Parry skill"

Exactly, it is called "Current Defence and Parry skill", not "Current Defence skill" or "Current Defence, Blessed, Experience, X and Parry skill" - parry is singled out.

I can understand what you are saying, but it also makes excellent sense the other way around.

The way you are thinking of it (parry value used once to determine whether an opposing attack is a shield hit that reduces the damage you take, but not adding to defence skill) a shield does not actually help prevent you from being hit - it merely reduces damage you take if you manage to interpose it between yourself and an incoming attack that would otherwise deal damage to you. The damage may be reduced to 0 (in line with the general protection mechanism) but probably not in case of really strong opponents.

This seems in stark opposition to not only several shield descriptions in-game (the Shield of the Accursed, the Shield of Gleaming Gold, and the Aegis all explain how the one using them becomes harder to hit because it is difficult to focus on the wielder), but also how shields have traditionally had dual use in warfare, both deflecting and absorbing blows (some better at one than the other and also depending on their martial use).

As such it makes excellent sense to have shields' both add to defense (value A) and to determine a range in which there's a shield hit (value B). This requires two different values to really fine tune - and shields have that: the parry value (x) and the defense value (y); in other words x = b, y = A - x

The magical shields you talk about have special effects that fulfil the description. Fear and awe perform the mentioned function admirably. I do not know the description of the Accursed Shield, but I expect it has to do with the horror marking.

As for your explanation about needing two values, it fails to convince me because of the simple fact that shields also have a listed defence value. If they did not, it would be plausible (albeit a bit inflexible), but as is, it is a part of the representational argument for my interpretation. The standard shield has a defence value of -1 and parry value of 4. If shields were intended to add to defence as you say, it makes much more sense to display the defence value as 3, the parry value 4 and only count the parry value once. You do not lose any flexibility but gain a lot in clarity. And you need to do less overall work, if I understand you correctly. First deciding a defence value from which you then subtract the parry value in order to display it does not make much sense when the persons looking at the display are then supposed to add that parry value back in order to determine what is a shield hit.

Independent Light Infantry using a spear: attack 10, defense 13 - including shield +4, and protection 15/8 [S15]. Damage is 10 + 3 + DRN - DRN - relevant_protection at location hit when considering shield protection into the mix.

Defense decreases by 2 per multiple attack and by fatigue/10 and attack by fatigue/20.

Under these conditions and given two groups of statistically significant size of Light Infantry, I most certainly expect a fair number of hits from the very first round they are in melee range of each other, for the difference between attack and defense and even attack and defense+parry is rather small (3 and 7 respectively) and the RNG will have its say in the +DRN - DRN business; moreover, the little light infantrymen won't square off one by one - given an equidistribution over each infantryman over those enemy infantrymen he can attack, it is practically certain that some infantrymen will be attacked more than others (and hence be easier to hit for every attack after the first one) and given the number of size 2 figures per square, some a lot more.

It might come out differently if I actually spent the time on doing a real statistical analysis of the problem but at least my rough mental napkin map (without a napkin ) comes nowhere close to your conclusion that "LI vs LI with spears and shield should not be able to hurt each other at all in the first few rounds if non-shield hits only occurred at above another +4 on top of the 13 defense rather than at above 13.

I was unclear. Sorry about that.

Since we are talking about a decent number of troops, there will of course be some troops that are hurt, but relative to the number it will not be significant. My observation is of course that troops suffer more losses than they should, if parry was counted twice. Beating a difference of 7 is not easy (about 2/25) and though the majority of troops struck in a round will be struck twice (reducing their defence for the second attempt by 2), few will be struck more often than that. Beating a difference of 5 is also not that easy (a bit less than 1/7). Counting on that a rough 2/3 of those targeted are targeted twice, about 2 in 21 are actually hit this way. If we then, to simplify, assume that all hits are on protection 8, the chance to kill someone this way is about 1/73.
Defence drops with fatigue, but so does attack. In effect, relative defence drops by one after three rounds and goes down a notch again after eight rounds.

With fatigue and damage accumulation, deaths will be increasingly likely, but it takes a number of rounds for that to happen.

I will not pretend to have done a complete statistical analysis, because I have not, but the (very) rough numbers above just do not correspond with my in game experiences.

Edit:
For what it is worth http://forum.shrapnelgames.com/showthread.php?t=43615#5 is a post that explains defence and parry as I think it works.
Take it for what it is worth. I have not made an extensive search of the boards, I just took the first one I found that explained it.