the effects goes like this
Once per turn, when your opponent activates a Spell/Trap Card, you can negate its activation and destroy it. If this face-up card on the field would be destroyed, you can destroy another face-up "Six Samurai" monster you control instead.
wat i wan to know that its once per turn thing, refers to only my once per turn or include opponent?
same goes for great shogun shien
Special Summon this card (from your hand). Your opponent can only activate 1 Spell/Trap Card each turn. If this card would be destroyed, you can destroy a face-up "Six Samurai" monster you control instead.
thanks so much