Seigen was, along with Nomura Anchô (founder of the Nomura-ryû school of uta-sanshin), a student of Chinen Sekkô, who was in turn a student of Yakabi Chôki, who is attributed with the development of the kunkunshi system of written musical notation (tablature).
The Afuso style, like the larger Nomura-ryû school of uta-sanshin, employs kunkunshi notation. However, unlike Nomura-ryû, Afuso-ryû does not employ written notation for the vocal parts of a musical piece, focusing more strongly on oral transmission from teacher to student, and on vocal nuances too varied to be easily notated. Despite the power of adhering to written notation for conserving a tradition in its traditional form, ironically it is the Afuso style which is believed to be closer than the Nomura style to Yakabi Chôki's original Tô-ryû style of performance.
- "Afuso Seigen." Okinawa Compact Encyclopedia 沖縄コンパクト事典. Ryukyu Shimpo. 1 March 2003.
- Thompson, Robin. "The Music of Ryukyu." Ashgate Research Companion to Japanese Music. Surrey: Ashgate Publishing, 2008. p313.
- Dates on the Okinawan lunar calendar. May differ from the Japanese lunar calendar.