A 115-year-old Japanese woman, the world's oldest female according to some accounts, passed away Saturday at a nursing home near Tokyo, dpa cited news reports as saying. The cause of the death of Koto Okubo, who was born on December 24, 1897, was pneumonia, the major daily Asahi reported, citing her 88-year-old son, who lives at the same nursing home in Kawasaki. Okubo became the world's oldest living woman after the death of 115-year-old Dina Manfredini of the US state of Iowa, on December 17. Jirouemon Kimura, a 115-year-old Japanese man, became the oldest living person in the world after Manfredini's death, the Guinness Book of Records said.