Kane Tanaka was recognised in a ceremony on Saturday at the nursing home where she lives in Fukuoka, in Japan's south-west.
Mrs Tanaka wakes up at 6 am every morning and passes the afternoons by studying mathematics and practicing calligraphy.
Before Tanaka, the previous oldest living person was Chiyo Miyako, who died past year at age 117.
"This right now", was Tanaka's reply when asked which part of her long life she enjoyed the most.
Her family and the mayor were present to celebrate the occasion.
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"It gives me a great pleasure to confirm Kane Tanaka is the oldest person living aged 116 years and 66 days as of 9th March 2019", Guiness World Records judge Kaori Ishikawa said. One of Kane's favourite pastimes is a game of Othello and she's become an expert at the classic board game, often beating rest-home staff. That title has been held by France's Jeanne Lousie Calment for the past 22 years, who died in a nursing home in southern France in 1997 at age 122.
The world's oldest person, a 117-year-old Japanese woman, has died.
The oldest person prior to Ms Miyako was also Japanese.
People from Japan tend to take top honors on the world's oldest person list, the Associated Press reported. She finally achieved the dream she had since she was 100.
Although changing dietary habits mean obesity has been rising, it is still relatively rare in a nation whose culinary tradition focuses on fish, rice, vegetables and other food low in fat.
Jeanne Louise Calment of France now holds the title for oldest person ever in history, with a final age of 122.