Thirteen years before the start of the series, Gyoncorde Plaza was one of the places Queen Otohime would approach every day to make her speeches about how humans and fish-folks should be united. She chose to make personal appearances in order to remove the boundaries between herself and the people, in order to increase influence. The signatures for her petition were kept in a box, where people were free to drop them in or retract them.
After returning with a World Noble's support, Otohime managed to get far more signatures than the box could hold, but one day the box was set ablaze. The arson was committed by a human pirate who was also believed to have then shot Otohime in the midst of the chaos. Hody Jones, then a soldier of the royal army, took the supposed culprit and held him high on a rooftop of the plaza and screamed out loud for the entire community to hear that it was a human who assassinated Otohime.
In truth, Hody paid the pirate to set the box of signatures on fire, and then Hody himself shot the queen. After the queen's death, Hody then shot the pirate and used him as a scapegoat.
Fish-Man Island Arc
When Hody, now a pirate captain, and the New Fish-Man Pirates took over Ryugu Palace, they declared that in three hours after the takeover, they would execute King Neptune in the plaza in order to cement Hody's position as the new king.
Eventually, when Jinbe, Shirahoshi and Megalo feigned capture, they secretly bought along the Straw Hat Pirates, who then proceed to free the Neptune family, retrieve the World Noble's letter from Hody's grasp, and do battle against the New Fish-Man Pirates. During the battle, the underground of the plaza has been heavily dug up by Daruma and Tony Tony Chopper.
Halfway through the battle, the great ark Noah approached the plaza and blanketing it in a huge shadow, having been thrown by Vander Decken IX directly at Shirahoshi. The princess, being locked on by Decken's powers, lured the ship away from the plaza and Fish-Man Island.
Once the battle has ended, the princes brought Hody and Decken back to the plaza and put them in chains. Jinbe kept the New Fish-Man Pirates underlings and their human slaves in the plaza to await Neptune's decision. After Neptune returns to the plaza, he lets the human slaves go free and give the underlings penal sentences. It is also in this plaza where Neptune declared off-limits to the Fish-Man District.
- Gyoncorde Plaza is a pun on the Japanese word for fish, gyo (魚) and the Concorde Plaza in Paris, where King Louis XVI was executed.
- One Piece Manga — Vol. 63 Chapter 626, Otohime was shot by a pirate during the chaos within the plaza.
- One Piece Manga — Vol. 63 Chapter 621, Otohime makes her speeches within Gyoncorde Plaza.
- One Piece Manga — Vol. 63 Chapter 624, Otohime's petition signature box was left open for the public within the plaza.
- One Piece Manga — Vol. 64 Chapter 627, Hody screams out at the top of the plaza with the supposed culprit in his hand.
- One Piece Manga — Vol. 64 Chapter 632, Hody reveals to everyone at the plaza that he was the one who killed Otohime.
- One Piece Manga — Vol. 64 Chapter 628, Hody declares that he will execute Neptune in Gyoncorde Plaza.
- One Piece Manga — Vol. 64 Chapter 633, Straw Hat Pirates and Jinbe vs. New Fish-Man Pirates.
- One Piece Manga and Anime — Vol. 64 Chapter 636 and Episode 557, Tony Tony Chopper and Daruma dig tunnels under the Gyoncorde Plaza.