Shimazu was born in Nirasaki, Yamanashi Prefecture, on 7 July 1892. Her father was a teacher. She was married at 19 years old, and later had six children. In her spare time, she volunteered in her community as a sewing tutor.
Between the ages of 78 and 106, Shimazu lived with her son. After falling and breaking her hip, she moved into a nursing home in Yokohama, Kanagawa Prefecture. At the age of 108, following a visit by Yokohama’s mayor, she was reported to be in good health and could still support herself.
In September 2003, aged 111, Shimazu was reported as the 11th-oldest living person in Japan. She followed a strict daily routine, waking at 5 o’clock in the morning to clean and sew. One of her hobbies was writing; she was a member of a local calligraphy club.
Shimazu died on 14 December 2004 at the age of 112 years, 160 days. She was the fifth-oldest person in Japan, and was survived by all six of her children.