After the release of One Piece Volume 1 in 1997, Oda and his editor were worried about whether his first volume would sell well. They decided to hide in a bookstore and watch the customers. When they saw a boy buying the OP volume, Oda and his editor shouted with joy.
Oda (2018): I appreciate that One Piece characters are popular among women, but basically I want to draw them in a way that boy readers find cool and interesting. For example, Sanji is not only cool but also a pervert.
The ones that are liked by the same gender are trustworthy.
Oda (1998): When Shanks appears frequently in manga, you can assume that One Piece has entered the final saga. 
[source : Oda's talk show at Nakano Sun Plaza in December, 1998]
Oda: As a 17-year-old Luffy, there was no way he could defeat a strong enemy like Yonko. That is why we needed two years. This is to have Luffy's growth be supplemented by imagination. The reason I chose two years was because I didn't want to make Luffy that much of an adult.
Oda(2019): One Piece is not a bond of Straw Hats. I hate that kind of thing. When I was a kid, I was not happy with the ending of The Wizard of Oz, that the adventure is itself a treasure. That story was unacceptable. Luffy has a great journey, so give him a proper treasure.
Oda (2022): I knew that my audience would be disappointed if One Piece took a break, so it was a hard decision for me to take a break. But recently, young manga artists are growing up in Shonen Jump, and I feel relaxed that they will support me even if I take a break.
Oda (2016): I had conceived the initial plot of Film Strong World to dig into the secret of Nami's birth. The movie staff was shocked to read the content. The story became a little too touching, so I revised it to be more exciting for the young audience.
Editor Sugita: It's difficult to explain in one word what the One Piece as a treasure is.
Editor Naito: Stop it already. Since you said it's difficult to explain the OP in one word, I'll formally take the opposite opinion to protect our jobs. The true identity of the OP can be explained in one word.
When Kumamoto, Oda's hometown, decided to build statues of OP characters to support reconstruction from the earthquake, there were those who opposed the idea of wasting taxpayer money. But when it turned out Oda had donated $6 million to the town, all naysayers were silenced.
After Naruto ended, Kishimoto told Oda that he can now take a walk with his kid on a sunny day whenever he wanted. Oda was so depressed to hear that but he was motivated at the same time to draw OP for the future where he can take a walk anytime.(2018)
Oda: Considering my life expectancy, the Netflix TV drama series is One Piece's last chance to go global.
Oda (2015): Naruto is more popular than OP in the world, but I appreciate that it makes me jealous.
Kishimoto (2016): I wanted to surpass OP in manga, but I could not.
In 2020, Oda jokingly said that he’d like to start a new manga called “Two Piece” after One Piece ends. He also said in 2007 that he longed for Akira Toriyama’s style of releasing a short manga every now and then.
*Maybe we can expect spin-off manga after OP.
Oda (after September 11, 2001): There are adults who kill people saying this is justice or this is a holy war. There are children who see it. One Piece is far from the ending. Praying for world peace.
Oda (2012): One thing that motivates me to keep drawing One Piece is that I want to draw the final saga.
The final saga will be so amazing that it makes the Marineford arc look like nothing. Marineford arc was just a side trip to me. I didn't expect it to be so popular.
Oda (2007): If you want to revive a dead character, then don't kill the character in the first place. I've hated it since I was a kid when a character is resurrected because I felt the author's intention. 'Did he bring this character back to life just because he is popular?'
Oda (2018): I was really concerned about Ace's death. In order for Luffy to move forward, he had to go through a big ordeal. The reaction of the readers was beyond my imagination. It was something I had to overcome with Luffy. You can't do a long series just for fun.
Oda (2007): When I start an arc thinking, "This arc will end in 30 chapters ," it usually takes 3 times as long, 90 chapters. In fact, the story far in the future is the clearest. I have had a clear image of the final saga and the final chapter since the beginning.
In 1997, Oda told chief editor Torishima, who complained OP was boring, "If OP sells well, be sure to admit your defeat". It sold very well, and at the following New Year's party, Oda said, "I promised you, right?" Torishima replied, "Sure..YOU WON!! Are you satisfied?"
Editor Sugita revealed in 2017 that he had discussed with Oda whether they should change Corazon's unique smile to just a normal one. Oda decided to keep the smile. The editor said, "This smile is impressive because it fits his awkward but lovable personality."
Oda (2017): It is hard to talk about justice through Luffy's mouth, since he is a pirate. So I just make a simple conclusion that the other side of justice is another justice. This is one of the main themes of One Piece.
Oda (2018): The reason I don't want to draw scenes where people die is because I want to draw a party after the battle. If someone dies, you can't have an enjoyable party. A party is my ideal form of friendship. I want to end with One Piece with a big party.
After his doctor warned him that Oda could die early at this rate, Oda decided to take a walk twice a week.
(2020)
(2022)
The problem is how many years it will take to start the final saga..
