The standard difficulty to overcome the mental defenses of an unaware target is 10. Since the difficulty of most metaphysical attacks exceeds this number, success is automatic. This is typically only possible if the attack is imperceptible or if the target's perception is impaired in some way. A wary opponent who has reason to believe a metaphysical attack is imminent may act before his initiative to make a willpower roll which will serve as the difficulty an attacking psychic must defeat in order to effect the target. A target may also choose a "full defense" option. He takes no other actions in the round except to concentrate on resisting the metaphysical attack. In this case, the difficulty for the attacker is willpower + 10.