ソーサリー
カードを3枚引く。
一徹 ― この呪文を唱えるために青マナが3点以上支払われていたなら、占術3を行う。
If an effect allows you to cast a spell without paying its mana cost, you can't choose to cast it and pay unless another rule or effect allows you to cast that spell for a cost. Similarly, you can't waive a cost reduction unless that effect says you may.