A 114-year-old Japanese woman, the daughter of a kimono maker, was formally recognised on Wednesday as the world's oldest woman.

Misao Okawa said she was "very happy" to receive the recognition and a certificate from Guinness World Records. After a meal of her favourite mackerel sushi, Okawa nodded off as she sat in her wheelchair, her three-month-old great grandson, Hibiki Okawa, at her side.

But she woke up to speak to a reporter. Asked for her secret for longevity, she said it was to "watch out for one's health."

The recognition by Guinness World Records was a nice gift for Okawa, who will mark her 115th birthday next week. According to the Gerontology Research Institute, which verifies age information for Guinness, she was born March 5, 1898.