DEF
"Defense" redirects here. For the battle position, see Defense Position.
DEF (
If a monster attacks another with an ATK that is greater than the DEF of that monster, the Defense Position monster is destroyed, but the controller of the Defense Position monster takes no Battle Damage unless the attacking monster has a "piercing" effect where the difference between ATK and DEF is dealt as Battle Damage. If the atk is the same as a face-up defense position monster both monsters are destroyed.
If the same situation is reversed, where the ATK is lower than or equal to the opponent's monster's DEF, both monsters remain on the field, but the controller of the attacking monster takes Battle Damage equal to the difference between the ATK and DEF values.