QUOTE (toturi @ Apr 27 2008, 08:55 PM)

Except that there is no such thing as a Full Block. Full Defense with unarmed or with a melee weapon are both called Full Parry.
Says who?
The rules pretty clearly state there are SEVEN options for melee defense. Parry, block, dodge, as well as Parry + Full Defense, Block + Full Defense, and Dodge + Full Defense. Not to mention the actual Full Parry option (Reaction + melee skill + melee skill). The mitigating factor being whether you are holding a weapon or not, or if you just plain decide to move out of the way.
If you don't want to call Block + Full Defense by the term "Full Block", then fine. But I'm not sure why there is confusion in this. +1 die for Full Parry pretty clearly only applies to 1 form of melee defense: Full Defense w/ melee skill x2 instead of the melee skill + Dodge. +1 (or +2) die for block pretty clearly applies to 2 defense options: Block and Block + Full Defense.
The real question should be: Can you Full Parry while unarmed?
To avoid any further confusion here is the relevant text from each book:
QUOTE (SR4)
Defenders have three choices for defending against unarmed attacks. If they have a melee weapon in hand, they can parry the attack by rolling Reaction + the appropriate weapon skill. If they have Unarmed Combat skill, they can choose to block by rolling Reaction + Unarmed Combat. Or they can simply dodge out of the way using Reaction + Dodge.
Melee defenders can also choose to go on full defense (p. 151), and add Dodge skill dice to their defense roll.
QUOTE (Arsenal)
+1 die for Full Parry; +1 die on melee block (but not dodge or parry) Defense Tests (may be taken twice for a cumulative +2 dice)
And while I have not personally taken karate, many of my friends have, and some of them have indeed received weapons training, so +1 to parry is not completely unrealistic, historically speaking.