Episode 19

"Past of the Three Swords! The Promise Between Zoro and Kuina!" is the 19th episode of the One Piece anime.

Short Summary
While Usopp and Luffy fool around with the ship's cannon one day, Zoro dreams about his childhood and the promise he made to Kuina before her untimely death.

Long Summary
While out at sea, Luffy found a box of cannonballs in Going Merry Storeroom and brought it onto the deck. Nami finds a place on the map where they can go to practise shooting them. This gets Luffy all excited. This episode flashes back to Zoro's childhood.

Zoro was a doujouyaburi, collecting dojo signboards. Kuina the daughter of a dojo master accepts Zoro's challenge. Bow to the gods, bow to your opponent, begin! Smack, smack with just two shinai strikes Kuina sends Zoro flying to the ground. Zoro gets up and strike a great "two sword/shinai technique" pose. Zoro charges towards Kuina, smack one hit right in between the eye, Ipon! Zoro have loss. Zoro joins the dojo and swears that he'll beat Kuina one day. Thus begins his training, Zoro gets stronger by the day but still can't beat Kuina. On the 2001st challenge they used real Katanas, during the fight she commented that Zoro lacks the stamina to carry two swords. Kuina is still undefeated. After the fight she consoles Zoro, as they grow older Zoro will eventually surpass her.Kuina tells Zoro that a woman can never be the world's greatest swordsman. Zoro disagrees and challenge her to compete and see who between them will become the world's greatest swordsman. Kuina accepts.

Kuina is dies after falling down the storage room stairs. She was looking for her katana whetstone. Zoro received that news while training. The master thanks Zoro for joining the dojo and motivating Kuina to train hardest. Zoro ask for Kuina's katana. He swears that he'll keep the promise made with Kuina, to become the strongest swordsman in the world. The master leaves Kuina's soul and dreams with Zoro. Eight years have passed and it's time for Zoro to leave the dojo to fulfill that promise.

Back to the present, Luffy and Usopp practice shooting cannons, Usopp hits the target in a single try. Unknown to them, they have hit someone Yosaku. Later, back in the cabin the Mugiwara Pirates is having a discussion about adding a new crew member either a musician or a cook, they hear a commotion on the deck, Luffy goes out to check. Johnny whose partner was hit is seeking revenge. Zoro recognise Johnny's voice. They were friends back in the days when he was a pirate hunter. Zoro asks Johnny why he is alone and where is Yosaku.