Parrying Heavy Weapons (p. B376) states:
"The same is true for unarmed attacks from high-ST creatures.
For the purpose of these rules, treat a punch, kick, bite, etc.
as a weapon with an effective weight of 1/10 the attacker’s ST."
So, for the character have ST10 and broadsword (3 lb.),
unarmed attack more than ST 90: Risk to break weapon.
unarmed attack more than ST 200: Cannot parry.
And see
http://forums.sjgames.com/showthread.php?t=87090&page=4[/QUOTE] #32 - #35.
If use BL/20 instead of ST/10,
then,
unarmed attack more than ST 30: Risk to break weapon.
unarmed attack more than ST 45: Cannot parry.
(for the character have ST10 and broadsword (3 lb.))