Further On Shields

"The Old Witch had a menagerie of Familiars with her. Some were like small animals. Others like insects. One looked a small boy, but couldn't have been her child. Another was a wooden box beset on a set of steel pins that it scurried around on. They gathered around as I approached. Silently she gestured to the menagerie and they scurried to the other corner of the cabin."
-Anis Al-Farid, Explorer of Nod

I did some further refining of the calculations for Armor as per my reflections on this post. As a result I have further refined my thinking on Shields. Here is how they currently work:

A Shield is used in one of your Hands slots: in the Off Hand paired with a Weapon in the Main Hand. Equipping a Shield has three effects. Note: I talk about the various Weapon Styles in more detail previously in this post.

1. A Shield confers a passive bonus to Armor Class, Damage Reduction or even Special Resistance -- depending on the Shield itself.
2. A Shield opens up the option of Blocking in response to an Attack. This immediately increases your Armor Class by 4 -- though some powerful Shields increase BOTH Armor Class and Special Resistance. This move requires a Stun Save as with other defensive actions whose difficulty (Easy, Standard or Hard) depends on the Shield. Blocking with a Shield you do not have the Strength to wield effectively automatically Stuns.
3. A Shield can be used to make a Basic Attack which triggers an Opportunity Attack with your Main Hand Weapon when rolling Natural-Evens (as with Dual Wielding). Using a Shield in this manner negates the passive bonus to defense until your next Action. Attacking with Shield you do not have the Strength Requirement to wield is a Clumsy Attack as with other Weapons. Also: the Opportunity Attack triggered by this move follows the same rules as Dual Wielding Weapons, Requires Agility of 2, otherwise the Opportunity Attack is Clumsy.

Also: Fighters who have Proficiency in Shields use their Shield for the making the Advanced and Power Attacks associated with the Proficiency, not their Main Hand Weapon.

Some Examples:

Iron Buckler (Light Shield, Requires: Strength 1)
This small, round shield wraps around the forearm and provides decent protection. 
+1 Damage Reduction, Blocking: Easy Save
+0 Attack, 1d6 Damage, Scaling Grade: (Strength * 1.0)

Composite Tall Shield (Large Shield, Requires: Strength 1)
This tall, rectangular shield is made of wood inside a reinforced iron frame.
+2 Damage Reduction, Blocking: Normal Save
+0 Attack, 1d6 Damage, Scaling Grade: (Strength * 1.0)

Strange Leather Shield (Light Shield, Requires: Strength 2)
This circular shield is a steel frame which has the black, bubbly hide of an unknown Ur-Beast stretched across it.
+2 Special Resistance, Blocking: Easy Save
+1 Attack, 2d6 Damage, Scaling Grade: (Strength * 2.0)

Who didn't love the combat in the movie 300?