Rule · Chapter 7
cr:7.5.2
First, damage is calculated for the attack-target(s). If the power of the attack is greater than the sum total defense value of the defending cards for the attack-target, the attack hits the attack-target for {p} damage equal to the difference.
Example: If the power of the attack is 6, and there are two defending cards with a defense 3 and 2 respectively then the sum total defense value of the defending cards is 5. The power of the attack is greater than the sum total defense, so the attack-target is dealt 6-5=1 {p} damage.