(Copied and pasted from Matt Peddle's TCGplayer article) : Book of Moon is another card that can help Black Rose resolve it's effect. In the finals feature match between Nguyen and Kwan the eventual Champion used Book of Moon to play around Kwan's Effect Veiler twice in the same match. Effect Veiler negates the effect of a monster as long as it's face-up on the field. You can chain cards like Torrential Tribute or Book of Moon to either turn the targeted monster face-down or remove it from the field, similar to the way you'd play around Skill Drain. Both of these cards can be put on the chain to Black Rose Dragon's effect, so if your opponent chains Veiler's effect to try and stop your Black Rose you can chain either of these and ensure the effect resolves.
Once again what could be considered the best play in this scenario will actually play into your hands. Let's say you've got Goyo Guardian, Book of Moon and Solemn Warning on the field withEffect Veiler in hand. Your opponent summons a tuner and is capable of making a level seven or six Synchro monster. You could stop the Synchro summon from being possible with Book of Moon or you could wait. You decide to wait, knowing you can negate Black Rose or Brionac with Effect Veileror could Solemn Warning an opponent's Goyo Guardian. Not only do you save Book, a much more versatile card, but you will get to steal your opponent's Synchro monster with Goyo Guardian next turn. Your opponent Synchro Summons for Black Rose Dragon, activates it's effect and you chainEffect Veiler. Your opponent chains Book of Moon to turn Black Rose face-down and there's nothing you can do in response. You lose everything on the field because you tried to make the most advantageous play.
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Which mean that if Effect Veiler negates Black Rose Dragon, you can throw Book of Moon or Torrential Tribute out to help it resolve its effect, as STATED BY MATT PEDDLE ABOVE ^
Awesome. This is because Effect Veiler negates the monster's effect while face up on the field. Torrential puts BRD in grave, and Book places BRD face down so they aren't negated by Effect Veiler.
Now, I DIDN"T know that at first, and what puzzles me is the missing of timing etc, but if BRd is a mandatory effect i guess it makes sense although it still doesn't seem right.
OH WELL its Yugioh, and Konami makes this rulings, and we must take advantage of this for our selves.
I guess that makes Book of Moon even more versatile than before , being able to overwrite Effect Veiler.
Though I suppose that doesn't work for Trishula.