Masu Koido (22 January 1907 - 14 November 2018) was a Japanese supercentenarian whose age is currently unvalidated by the Gerontology Research Group (GRG). She was the oldest known living person in Gunma Prefecture, Japan.
Masu Koido was born on 22 January 1907 in Japan. On 26 August 2016, then aged 109, she became the oldest known living person in Gunma Prefecture, following the death of 112-year-old Mumeno Sakurai. She was reported as such in September 2016 and 2017.
Koido lived in Minamikimura, Gunma Prefecture, Japan. She passed away 14 November 2018 at the age of 111 years and 296 days.
- Gunma Prefecture Report, September 2017
- Limbo mention