- Born: 1878
- Died: 1952
- Other Names: 太田恒二 (Oota Tsuneji), 物外 (Butsugai)
- Japanese: 佐藤恒二 (Satou Tsuneji)
He was born in Komoro-machi, in Nagano prefecture, the second son of Ôta Hiroshi, a judge in the Chiba prefecture judicial system. In 1900, he married the third daughter of Satô Shunkai, head of the Sakura Juntendô medical school, and was adopted into the Satô family, changing his name from Ôta Tsuneji to Satô Tsuneji.
After graduating from the (pre-)medical program at the Chiba prefecture First High School (which later became the medical school of Chiba University), in 1901 he traveled to Europe to study medicine further. Returning to Japan, he studied under Shunkai at the Juntendô for a time, and following Shunkai's death in 1911, succeeded him as head of the institution. In addition to maintaining the original Juntendô school & research center, Tsuneji worked to establish an additional Juntendô Hospital, a short distance away, near the present-day site of the JR Sakura train station.
Tsuneji also served as the head of the Society for Japanese Medical History for a period, and worked to ensure that the precious documents and artifacts held by the Juntendô would be conserved and secure.
A passionate calligrapher, Tsuneji employed the signature Butsugai as a poetic pseudonym.
- Pamphlets available at the Juntendô Memorial Buildings Museum.