The Strongest, Invincible Sword Style is the 47th episode of the Katekyo Hitman Reborn! anime.
The battle for the Ring of Rain between Yamamoto and Squalo is announced. Hibari causes a commotion at the school as the battles have caused major damage to the grounds. Dino reveals that Squalo once defeated the Swords Emperor of the old Varia and that Yamamoto's Shigure Soen Ryu is useless against him. Yamamoto receives a shinai from his father that transforms into a katana only when using the Shigure Souen Style.