One Piece Chapter 5, page 14-15: CHAPTER 5: THE KING OF THE PIRATES AND THE MASTER SWORDSMAN

The next day, a dojo student runs up to Zoro with tragic news: "ZOLO! THERE'S BEEN AN ACCIDENT! IT'S KUINA! SHE FELL DOWN THE STAIRS... SHE'S DEAD!!!" Zoro is completely devastated. At her funeral, Zoro stands before her covered body, crying as Koushirou tells him, "HUMANS ARE FRAGILE THINGS, ZOLO..." Zoro begs his master, "SENSEI! MAY I HAVE HER SWORD?" Koushirou replies, "...I SUPPOSE SO..." Zoro holds the sword tightly, weeping and screaming, "I'LL HAVE TO KEEP THE PROMISE FOR BOTH OF US. I'M GOING TO BECOME SUCH A GREAT MASTER SWORDSMAN THAT MY NAME WILL BE KNOWN EVEN IN HEAVEN!!!!

The flashback ends, returning to the present courtyard. Zoro, facing the firing squad, thinks, "I CAN'T DIE YET!! I PROMISED HER!" Captain Morgan commands, "FIRE!!!" Just as the Marines are about to shoot, Luffy launches himself out of the base window using his rubber powers, shouting, "GUM-GUM... ROCKET!!!" and crashes down into the courtyard.