- Other Names: 山口辰吉 (Yamaguchi Tatsukichi)
- Japanese: 山口 瑞雨 (Yamaguchi Zuiu)
He began teaching at the Okinawa Normal School (Okinawa shihan gakkô) in 1896.
In 1908, he founded the Tansei association, which produced Nihonga paintings of Okinawan subjects. Yamaguchi submitted a number of his own paintings to exhibitions held by the Japan Painting Association (Nihon bijutsu kyôkai).
Yamaguchi submitted a six-fold screen painting to the sixth Bunten exhibition in 1912 depicting a scene of the Ryukyuan king. The work was admitted into the first class of Nihonga works in the exhibition. While a number of Okinawan artists were showing in major national exhibitions at this time, Yamaguchi was in a meaningful sense appropriating their position, representing Okinawa but doing so as a Japanese person, with works in a Japanese style. The screen painting was likely based on direct observation of the Ryukyu investiture crown, Engaku-ji, and other elements of Ryukyu Kingdom heritage; it was harshly criticized, however, by Okinawan art critics such as Ryûkyû Shimpô writer Sueyoshi Bakumontô who asserted that it didn't reflect Ryukyuan spirit and was totally lacking in Ryukyuan character.
- Junko Kobayashi, "The Demise of Ryukyuan Painting," Okinawan Art in its Regional Context symposium, University of East Anglia, Norwich, 10 Oct 2019.
- Miyazato Masako 宮里正子, "Geijutsu, Geinô katsudô he no shinshutsu"「芸術・芸能活動への進出」, Naha onna no ashiato, Naha joseishi (Sengo hen) なは・女のあしあと 那覇女性史（戦後編）, Naha-shi sômubu josei shitsu 那覇市総務部女性室（ed.）, Naha: Ryukyu Shimpo-sha (2001), 377-378.