If you have a card like stamping destruction or delta crow that requires a monster be face up to be able to activate it and someone uses Book of Moon on the monster and it was your only monster at the time then do they still get the effect?

I'm thinking it says 'activate when blah blah is face up' and when you are activating it they are face up - but there I go thinking again. I don't have access to any rulings sites so any help is appreciated (Inu? :D)

Also I'm hearing that delta crow is ruled differently even though it has the same text essentially.

Usually, if a card says something like, "Activate only if you control a face-up <whatever>", then you only need that monster(s) face-up to activate the card, not to let it successfully resolve unless rulings say otherwise.


The number of “Blackwing” monsters on the field is only an activation requirement. If the number of Blackwings is no longer correct when “Delta Crow - Anti Reverse” resolves, its effect is still applied