Superheavy Samurai Swordsman

The monster effect "(1): When this card is Normal or Special Summoned: You can activate this effect; change this card's battle position" is a Trigger Effect that can be activated optionally. (This effect does not target. It can also be activated during the Damage Step.)

The monster effect "(2): After damage calculation, when a 'Superheavy Samurai' monster you control battles an opponent's monster: That opponent's monster's ATK/DEF become 0" is a Trigger Effect that must be activated after damage calculation when a "Superheavy Samurai" monster you control battles an opponent's monster. (This effect activates not only when "Superheavy Samurai Swordmaster Musashi" itself battles, but also when another "Superheavy Samurai" monster you control battles.)