Japanese sushi legend Jiro Ono won three Michelin stars for more than a decade, the world's oldest head chef to do so. He has served the world's dignitaries and his art of sushi was featured in an award-winning film.

After all these achievements and at the age of 100, he is not ready to fully retire.

"I plan to keep going for about five more years," Ono said last month as he marked Japan's "Respect for the Aged Day" with a gift and a certificate ahead of his birthday.

What's the secret of his health? "To work," Ono replied to the question by Tokyo Gov. Yuriko Koike, who congratulated him.

"I can no longer come to the restaurant every day ... but even at 100, I try to work if possible. I believe the best medicine is to work."

Ono, the founder of Sukiyabashi Jiro, a tiny, 10-seat sushi bar in the basement of a building in Tokyo's posh Ginza district, turned 100 years old on Monday, October 7.

Seeking perfection
In one of the world's fastest-aging countries, he is now among Japan's nearly 100,000 centenarians, according to government statistics.

Born in the central Japanese city of Hamamatsu in 1925, Ono began his apprenticeship at age 7 at the Japanese restaurant of a local inn. He moved to Tokyo and became a sushi chef at 25 and opened his own restaurant 'Sukiyabashi Jiro' 15 years later in 1965.

He has devoted his life seeking perfection in making sushi.

'I haven't reached perfection yet,' Ono, then 85, said in 'Jiro Dreams of Sushi', a film released in 2012. "I'll continue to climb trying to reach the top but nobody knows where the top is.

Director David Gelb said his impression of Ono was "of a teacher and a fatherly figure to all who were in his restaurant."

At the beginning, Gelb felt intimidated by the "gravitas" of the legend but was soon disarmed by Ono's sense of humor and kindness, he told the Associated Press in an interview from New Orleans. "He's very funny and very sweet."

"I was filming an octopus being massaged for an hour, and he was worried about me," Gelb recalled. Ono told him he was afraid the director was making the most boring film ever and that he could leave if he wanted to.

"He was so generous and kind of humble of him to do that," Gelb said. "Of course I was determined, and I was like, no way ... Massaging the octopus to me is fascinating."