One Piece Chapter 5.3, page 7-11: The Pirate King and the Great Swordsman

Luffy finds three katanas and wonders which one belongs to Zoro. Looking out the window, he notices the commotion at the execution grounds. Outside, Captain Morgan orders his men to surround the base and prevent Luffy's escape.

Captain Morgan stands before Zoro, boasting of his great strength and calling Zoro garbage. The firing squad prepares to shoot. Facing death, Zoro remembers his past and resolves that he cannot die yet.

Zoro's childhood flashback begins. A young Zoro loses his 2000th match to Kuina at the dojo. Kuina taunts him for being weak despite using two swords, while the other dojo students defend Zoro's strength.

The dojo master, Koushirou, consoles Zoro after his loss. Zoro is frustrated that he cannot defeat Kuina despite being able to beat adults. He passionately vows to train harder and become the world's number one swordsman.

One night, Zoro challenges Kuina to a duel using real katanas instead of wooden practice swords. Kuina accepts his challenge, and they prepare to fight under the full moon.