Effect
If your opponent Special Summons a monster(s): You can change as many Attack Position "Superheavy Samurai" monsters you control as possible to Defense Position, and if you do, the ones changed by this effect gain 500 DEF until the end of this turn.
The monster effect "①: If your opponent successfully Special Summons a monster(s): You can activate this effect; change all Attack Position 'Superheavy Samurai' monsters you control to Defense Position, and if you do, they gain 500 DEF until the end of this turn" is a Trigger Effect that can be activated optionally. (It cannot be activated during the Damage Step.)
The process of "change all Attack Position 'Superheavy Samurai' monsters you control to Defense Position" and the process of "they gain 500 DEF until the end of this turn" are treated as occurring simultaneously.
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