Tamagawa was born as Suma Hiraiwa in Yonezawa, a town in Ninohe City, Iwate, on 14 March 1899 as the third daughter of Osamu and Haru Hiraiwa. She had 13 siblings. She married Ukichi Tamagawa aged 22 in 1921; the couple had seven children.

Tamagawa worked in agriculture until she was 95 years old, and was still preparing meals for her family as a centenarian. In December 2000, aged 101, she was admitted into a Ninohe nursing home due to deteriorating mobility.

On 19 May 2008, at the age of 109, Tamagawa became Iwate’s oldest resident following the death of Fumi Nishizawa, a few weeks her senior. At 110, she was reported to be dexterous, enjoying origami and sewing, as well as peeling her favourite apples with a knife. A staff member of her nursing home commented in an interview with the city’s public relations paper that Tamagawa had a humble, kind, and caring personality.

Tamagawa died in Ninohe, Iwate, on 23 December 2011 at the age of 112 years, 284 days. Her successor as the oldest living person in the prefecture was Saki Kanda, then aged 108.