Guard is a technique performed by holding the G button ("X" or "A" on PlayStation or Xbox controllers, respectively). When guarding, lateral movement is not allowed, and all damage to the guarding player's health is negated (though there are skills which can bypass this). In Soulcalibur IV, attacks made upon a guarding opponent will deplete their Soul Gauge, which, if continued, will force the opponent into Soul Crush, thereby discouraging extended guarding. A player can guard standing or crouching. A standing guard blocks against high and mid attacks while a crouching guard blocks against only low attacks (high attacks miss crouching players entirely). Players cannot guard while prone, downed, or in the air.
From a guard position, a player can jump, hopping into the air for a very brief time. While jumping, a player's guard is down, allowing for attacks (including attacks which only work on opponents in the air). However, low attacks miss a jumping opponent entirely, and some attacks can only be performed from a jump.
A Guard Impact is a defensive move related to Guarding.