How Blocking works

[Roarikk]

I have recently rolled a Shaman and wanted to learn more about how blocking works in WoW. I am aware that strength increases the amount of damage you can block, but not the block rate itself.

Currently I have a block percent of ~10%(with the talent). What I would like to know is whether a block is a complete mitigation of damage like parry, or only blocks the stated amount on a shield.

Ex1 Mob attacks for 100 and I block, my shield has 30 block on it
Does it:
A: reduce the attack to 0 damage, like parry
B: reduce the damage to 70 (assuming no other mitigation other than block)

If the answer is A, then why do we have additional block stat on the shield? If the answer is B, what governs how often this occurs?

Or is it like stoneskin totem, an effect that is always on, like:
Ex2 Mob attacks, you automatically will reduce the damage to 70, and have a chance to block all damage by ~10%.

My goal is to find the best way to reduce damage for offtanking in 5man and eventually 10 man instances ( I am aware how how poor a shaman tank would be in MC BWL etc.)

Any feedback would be greatly appreciated!

[Havoc Jack]

B. You have a block % that gives you a chance to block the amount on your shield. Plus whatever strength gives you, I don't know numbers for that.

You can increase your block % by increasing your defense skill, by 0.04% per point of defense.

[Roarikk]

Thank you for the reply

So there is a ~10% chance to block 30 damage, but you cannot block the entire attack. Only parry and dodge reduce damage to 0?

30 damage every 10 attacks isnt really a big deal when mobs attack for several hundred. So I can assume the only real benefit of a shield is its AF and stats/proc and block is just a bonus random mitigation.

[Kail]

The amount you block is increased by your strength; 20/22 str = 1 more damage blocked are the numbers I've heard.

[AlecZorab]

The biggest value of block won't be much use to a shaman, unless you mt in raids a lot :(

Blocks prevent crits and crushing blows (in pve) so everytime you block, you might have just saved yourself getting 1-shotted. It's kind of hard to appreciate, expecially since you've no way of knowing if it was a crushing blow you didn't just get hit with :)

On paladins it's 20str/block. I imagine it's the same for shaman.