Portrait and Black Belt

[Luxatos]

Suppose a player who is behind in Prizes uses Smeargle's Portrait and finds Black Belt in his opponent's hand. Can he use it to increase his Pokemons' attacks? I would guess yes, but since the effect is similar to Buck's Training I was wondering if Black Belt similarly had to be in play for it to have an effect.

 

[PokePop]

Yes. Black Belt does not say anything about having to be in play to work.