Kamato Hongo turned 115 years old Monday, her first birthday since she became the world's oldest person in March.
Her family says Hongo stays awake two consecutive days and then sleeps for two days at her Kagoshima home.
Though she cannot walk without assistance, she enjoys singing and "dancing" with her hands.
Hongo lived in the town of Isen on Tokunoshima Island until the age of 77.
Isen is known as the town in which Shigechiyo Izumi -- whom the Guinness Book of World Records officially recognized as the oldest living person until seven years ago -- lived to the age of 120. He died in 1986.
Meanwhile, Yukichi Chuganji, 113, a native of Ogori, Fukuoka Prefecture, is now the oldest man in the world.