A Block, not to be confused with a Parry, is a way of preventing damage done to the character using it. In order to block, one must face the opposite direction of the foe, and should block automatically when attacked.
Blocking can be done standing, crouching, and in the Street Fighter Alpha series, in air. Allowing attacks to be blocked depends on what angle the attack is coming from and which direction the player blocked;
- If one is attacked via crouching attack by the foe, then the player must do a crouching block -- the standing block will not prevent the attack.
- If one is attacked while standing, crouching or standing blocks are fine.
- If one is attacked via aerial means, a standing block must be used -- crouching will not do anything to prevent it (but could evade the attack).
When blocking a special attack (includes Supers), the blocker will receive Chip Damage. Grab attacks cannot be blocked, but in Street Fighter IV, a "technical" may be performed by attempting to grab a foe who tries to do the same and cancel out both attempts.
In Street Fighter Alpha 3, all characters have a "Guard" gauge which limits their ability to continuously block by putting a limit on it. Certain play modes (V-Ism specifically) allow a bigger Guard. In classic mode there is no gauge at all, however in addition to the lack of Supers.