Shields, for me, are either bucklers or bigger. Bucklers grant the parry and defensive capabilities, and anything bigger gives extras.

+15 to parry with no -20 for off-hand (as per RAW) and -20 to attack with (as per RAW). I count them as a door of the material (so AP1 for wood, AP4 for re-enforced plas-steel/Kevlar) and they grant that armour/AP to the arm (stacking) and to a body part (stacking) if the player admits he's being 'defensive' from incoming fire. Usually the body. If they stick it in front of their face, it helps but they can't see. 

The Rules are not helpful in being certain of any of this. Technically we can be strict, and say "no no, shields are shields" and leave it at defensive and parry capabilities… but everyone's seen the Arbites with the shield, it's a cool idea (esp. with the tiny window.) thankfully I've been lucky enough to work it out on a player-to-player basis, and apart from the shield having an exterminator mounted on it…

I am thinking that I want shields to be both a defensive weapon to be used to counter an enemys attacks (Parry) and also provide a form of protection/damage mitigation from attacks. I do not like the arbitrary ruling that a shield adds defense to arm+body only, as the body location hit by an attack is randomly determined and not affected by the targets actions (Ie, he can’t put his arm/shield first and choose to take the hit there, neither can he put his left foot to the rear to avoid hits there)

Neither do I want shields to just be extra armour that adds AP everywhere all the time. WFRP v1 did this, and it never sat well with me.

So I suggest the following: A shield-wielder may actively move his shield into position between him and an enemy/incoming attack by spending a reaction. The shield will now provide its AP vs that enemy/attack, but will NOT protect vs other enemies on that turn. 

The chosen enemy will now have to attack through/past the shield, but no penalties will be applied. The reduced damage he will inflict as a result of the shields AP can be thought of as both the shield absorbing impacts, and as the attacker having to push an attack past/around the shield and delivering a lesser impact than he would have done otherwise.

This applies to melee and ranged attacks equally, you have to choose where the shield protects from. For ranged fire we could use a 30 degree arc like the flamer template to determine which attackers are covered by the shield. Keeping the protection up like this while moving requires the Tactical Advance Action.

As a variant I am thinking about letting this reaction be a Parry, where a successful Parry test works as normal. But even a failed test will let the shields AP apply towards damage taken, which will also be helpful if the Parry does not stop all attacks from a Lightning Attack, for example. The shield might not be positioned to protect against that opponents other weapon, if he dual-wields.

In this way, even an unskilled fighter can gain some protection by hunkering down behind his shield, at least if only fighting one opponent. A skilled opponent might use Feint to prevent the shield being deployed successfully against his attacks, but I think that the defensive bonuses a weapon grants to Parry should also apply to resist feints. Agree? Disagree? Why?

So, to summarize, and add some other elements I haven’t discussed:

1. Weapon craftsmanship WS bonus applies to all WS tests, including parries, Feints and other maneuvers.
2. You may position your shield to defend vs 1 Opponent/Attack with a Reaction/Parry. The shield will provide AP protection vs this attack.
3. Dual-wielding weapons give the ability to attack with both weapons as one Action, with a -20 modifier to both weapons (reduced to -10 with Ambidextrous). Therefore, it is only fair that dual-wielding (which includes sword+shield) also lets you parry with both as one Reaction. So if facing down a dual-wielding swordsman, you have the ability to defend against both his weapons. Position your shield/parry with shield vs one hand, and parry with your sword vs the other.

Different shields will have different AP values depending on make and material, and some might have Primitive AP.
 

Having worked on Riot/SORT RRTS teams with actual shield training i can say that the one thing many dont realize is how vulnerable you become to anyone NOT weilding a weapon ( bare handed )…the person with the shield is actually then at a disadvantage IF they stay on the defensive…since its very easy to get the shield grabbed on edges etc and having yourself yanked off balance unless your in a shield-wall formation type thing where you have the side cover..and even then its as simple as grabbing the top and pulling you forward off balance ( a actual tower shield is made from somewhere between 1/4 - 1/2 thick lexan and weights in around an avg of 30-40lbs…making your center of gravity slightly off towards the front-front/side its on…

As long as were talking ranged combat or someone weilding a 2-handed weapon though…..the shield can grant you the ability to parry any attack with insufficient Pen to get through whatever the shields effective AP is…but would definitely count AS your parry ( if you have more than one for whatever reason then so be it )  
 

I do like and will use the idea of the new Talent for Shield training ( perhaps taking it a bit further for ease of game mechanics and combat options ) as such:

Talent:

Shield Use = Grants PC ability to use shields effectively for cover and defensive actions ( granting the +15% to parry/negate attacks etc )

Shield Mastery = Grants PC the ability to utilize the shield AS a weapon ( IE shield bashing Pen-0 Dmg-1d5(+S bonus )+ AG test to avoid knockdown ( degree of difficulty determined by GM based on size and relative strengths of opposing sides )

This method would save game time and debate on things by giving clear ideas as to what the shields could/couldnt be used for with the associated talents..

And yes if you had 2 weapon wield melee..you could very easily get evil with a "sword and board" using the shield to attack as often as the sword ( was a very common method in middle ages in europe - feint swing wth sword…once enemy commits to parry launch shield bash to disorientate and put enemy weapon off angle for counterstrike/defense and land primary actual strike before enemy can regain footing ) BUT that did take alot of practice and training ( hence the associated talents as requisites for taking that needed time to learn how to do it..it isnt as easy as some think )

As for the AP of the shields and how much they cover..it depends on type of shield…a buckler would only grant the extra AP to the shield arm…and as bonus to parry ( their size and design are for just that ) but a larger full shield would grant the AP to the shield arm and body ( head if they raised it up to give that cover but would loose the body cover as well unless they ducked under the shield level…Tower shields truly can protect the shield arm body and legs at same time..head as well IF you duck below the top edges of it and loose sight of your target…If you use actual police style tower shields then you can duck below the shield top for head cover and still see your enemy due to fact that its made of transparent material ( but your enemy can see you too and what your about to try and pull ) …So it is a tradeoff…

Hope this helps some…

After much deliberation on the topic of sheild usage, we just came up with what me (GM) and a few PC's think is a good way to tackle this subject. PC is using a tower shield, 3ap, we decided to give the shield "wounds" 6, we also have decided to give the shield "body parts" so for a tower shield the digram is below.

3ap(6w)  |  3ap(6w)

3ap(6w)  |  3ap(6w)

3ap(6w)  |  3ap(6w)

So this towesr shield has 6 sections that can take 6 wounds each, and have 3 ap total, the shield, still only giving a total of 3 ap over all, but each section can take that much damage.

Thoughts?

I had to tackle this issue head-on when I was compiling things for the Macharian Handbook, since that was running a gamut of different shield types in The Inquisitor's Handbook and other books where this has been addressed. Might I encourage any interested parties here to example the way I tried to assess the often conflicting situation?

For a brief summary, I decided to consider shields as basically being Defensive melee weapons that are much easier to smack swords and axes out of your face with, but depending on the type, some can be used as cover (for a specified amount of APs) if you're stationary or taking the Tactical Advance action, while a few also grant you static APs to the arm and body locations - provided you aren't Surprised, that is.