One Piece Chapter 51, page 2-3: Roronoa Zoro Falls Into the Sea

The duel is watched by many spectators. On the balcony of the Baratie, the cooks, including Patty and Carne, look on with intense focus. The narrator declares, "The world's strongest swordsman, versus the Pirate Hunter Zoro...!" Nearby, in a small boat, Johnny and Yosaku cheer confidently, shouting, "There's not a chance someone can match our Bro!" Luffy stands quietly beside them, watching. Meanwhile, on his ruined flagship, Don Krieg sits slumped, staring at Mihawk in disbelief, thinking, "That man... just what did he do to this ship...!

Zoro clenches the sword in his mouth, glaring at his opponent, and asks, "Just what're you planning to do with that?" Mihawk has pulled a tiny, cross-shaped dagger from his necklace with a sharp "SHING" sound. Mihawk explains, "I'm different from those stupid brutes who'd go all out just to hunt a mere rabbit. Though you may be a swordsman of some renown, this is East Blue, the weakest of the four seas..." A map of the world appears, showing the four seas—North Blue, West Blue, East Blue, and South Blue—separated by the Red Line and the Grand Line.