The Perfect Block is a property of the block ability for shields and magick shields. Used by Fighters, Assassins and Mystic Knights.
A perfect block activates when the block button is pressed as an attack connects (within a few frames before it hits).
Success is signified by a brief white flash and grunting.
Unlike regular blocking, perfect blocking uses no Stamina.
Perfect blocking yields more powerful effects in tandem with other shield skills, such as Deflect, Reflect and the elemental counters of the Mystic Knight (such as Firecounter).
Elemental counters (Mystic Knights) require a Perfect Block and the core skill Reflect.
Perfect blocking is made easier (that is to say, the window of opportunity is increased by a few frames) by the Fighter augment Prescience.