How many limbs does it take to Block?

[SteveZilla]

Does Block require the use of one (or more) fully manipulatory Limbs?  What are the limits on "valid SFX" of a Block?

1) if a character has both their arms disabled does that render them unable to Block?
2) if a character is using their one (or more) manipulatory limbs by maintaining a Grab, are they unable to Block and maintain the Grab?

Presumably this would be identical for the regular vs Martial versions of these maneuvers, but if not please detail that (and if allowed, why the difference). 

[Simon]

It depends.

It depends on the character doing the blocking.  It depends on the attack being blocked.  It depends on the surrounding situation/environment.

It is entirely possible to block a punch with no limbs - simply moving into the strike at the proper time, preventing it from gaining any power (and leaving the blocker in an advantageous position).  It is also entirely possible that having a single arm occupied would prevent a character from being able to effectively block a downward, angled strike.

So:  up to the GM's dramatic sense (story telling).