Born in 1870 in Shizuoka prefecture, Koitsu moved to Tokyo at the age of fifteen. He later became Kiyochika's apprentice and moved into his home to study art and print design. It is through Kiyochika that Koitsu gained his trademark skill in the subtle use of light and shadow for his landscape prints. Koitsu lived with Kiyochika for 19 years and was considered more a member of Kiyochika's family than an apprentice. Although Koitsu first designed woodblock prints during the Sino-Japanese war (1894-1895), and later worked as a lithographer (around 1898 to 1905), he only became an internationally-renown artist after his chance-meeting with Watanabe Shozaburo, the founder of the Shin-hanga print movement, at an exhibition of Kiyochika's works in 1931 that marked the anniversary of Kiyochika's death. In 1932 he started to produce landscape prints in the shin-hanga style for Watanabe, the first being titled 'Cherry Blossom Viewing at Gion', and he went on to design a total of ten prints for Watanabe. He later designed prints for various publishers including Doi Sadaichi (known incorrectly in the West as Doi Teiichi), Kawaguchi, the Kyoto publisher Baba Nobuhiko, the publisher Tanaka Shobido, and the publisher Takemura.