A politically liberal, widely read, and philosophically independent Japanese Christian, Yamaguchi (Gengo) Gen was a sosaku hanga print artist born in Shizuoka Prefecture in 1896. 

At the age of twenty, Yamaguchi traveled with his father on a business trip to Taiwan, where he met artist Fujimori Shizuo at a local mountain hot spring. Yamaguchi was able to obtain several informal lessons in printmaking from Fujimori, which piqued his creative interest. Several months after his return, however, Yamaguchi joined a quasi-philosophical religious cult, renounced the financial support of his family, and became an ascetic. It was not until Fujimori returned from Taiwan that he reconnected with Yamaguchi and formally introduced him to Onchi Koshiro in 1923. Onchi asked Yamaguchi if he would donate his services to the Hanga Kyokai's annual show in exchange for alms. Yamaguchi agreed. He continued to visit Onchi at his home and was subsequently introduced to sosaku hanga artists Azechi Umetaro and Maeda Toshiro. 

Yamaguchi continued creating prints in his spare time and later submitted them for review. After confirming his acceptance into the annual Hanga Kyokai exhibition, Yamaguchi withdrew from the cult he had joined in order to study printmaking full-time. From 1935, he worked as a sosaku hanga print artist associating, particularly with Onchi, Azechi, and Maeda. Like his mentor Onchi, Yamaguchi incorporated natural and humanmade objects into his printing process to create abstract, nonobjective compositions, as seen in Poetry of Early Autumn, Human Beings, and Number 311. In 1937 Yamaguchi moved into a house near Onchi and began attending daily Ichimokukai sessions. He also exhibited with Kokugakai and Nihon Hanga Kyokai throughout the mid-1930s and became a member of the organization in 1943. Furthermore, he contributed to the Ichimokushu Print Collection, Recollection of Tokyo (1945), and Picture Album of Native Customs (1946). 

During the Pacific War, Yamaguchi evacuated to the fishing village Enoura (Numazu city, Shizuoka Prefecture) in 1944 and remained there for the rest of his life. He resurfaced briefly after winning major prizes at Ljubljana in 1956 and becoming the first Japanese citizen to win the Grand Prix at Lugano two years later in 1958. Yamaguchi Gen passed away in 1976.