Itooka died on December 29 at a care home in Ashiya, Hyogo Prefecture, central Japan, according to staff.
The supercentenarian, who loved bananas and a yoghurt-flavoured Japanese drink called Calpis, was born on May 23, 1908.
She was recognised as the oldest person in 2024 following the death of 117-year-old Maria Branyas, according to the Gerontology Research Group.
When she was told she was at the top of the World Supercentenarian Rankings List, she simply replied: "Thank you."
Born in Osaka, Itooka was a volleyball player in high school, and long had a reputation for a sprightly spirit, officials said.
She climbed the 3000-metre Mount Ontake twice.
She was married at 20 and had two daughters and two sons, according to Guinness.
Itooka managed the office of her husband's textile factory during World War II.
She lived alone in Nara after her husband died in 1979.
She is survived by one son and one daughter, and five grandchildren.
A funeral service was held with family and friends.
According to the Gerontology Research Group, the world's oldest person is now 116-year-old Brazilian nun Inah Canabarro Lucas, who was born 16 days after Itooka.
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