Card Rulings talk:Justi-Break

fansub
the effect of this card can only be activated during the battle when your opponent declares an attack on a normal monster or a monster "GEMINI" that is not treated as a monster and has its effect or monster effect card, wins the monster attack normal void This applies not calculate damage to your opponent, however, by resolution all other monsters on the field are destroyed as the monster effective as those who are upside down, just stay in the countryside void normal monsters.