Sōfū was involved in a major twentieth century innovation in nô texts. In 1929, he drew the illustrations for the Kanze School’s Kanze-ryû Shōwaban, nō play texts published by the Kanze School of nō. In 1937, with the publication of the Kanze-ryû Taiseiban Utaibon, Kanze Sakon, the head of the Kanze School, and Sōfū revolutionized nō texts by introducing line-drawing illustrations onto the pages of the texts.
Between the penultimate year of World War II in 1944 and Sōfū’s death in 1963, he actively created nō paintings and prints. Unfortunately, there is no catalogue of Sōfū’s oeuvre, although the Matsuno Geibunkan, a small museum dedicated to his work in Yotsukaidō in Chiba Prefecture, has a collection of his paintings and prints. In 1944, Sōfū provided illustrations for a republication of Noel Peri’s classic Le Nō.
Sōfū’s sketches and line-drawings also appear in the three volumes of English-language nō translations published in 1955-60 by the Nippon Gakujutsu Shinkōkai. In 1983, a committee headed by Itō Tatsuo selected one hundred prints (eighty-nine by Kōgyo and eleven by Sōfū) from the joint 1927 series, and republished them as Nōgaku meisaku hyakusen ("A Selection of One Hundred Nō Masterpieces".) The heads of all five nō schools approved the publication and their names appear on the title page.
Sōfū not only produced paintings and prints of nô subjects, but also in 1927 he painted his first of what would be a number of pine tree backdrops for nō stages: this first was in a private home of a former high-ranking retainer of the daimyō of Sendai, and ironically done in the same year that his mentor Kōgyo died of lead poisoning while painting a pine tree backdrop on a stage in the city of Utsunomiya. After World War II, Sōfū painted the pine and bamboo trees on the back of stages at Hakusan Shrine, the Shintô affiliate of Chūsonji Temple at Hiraizumi in Iwate Prefecture, at the Yamamoto nō stage in Osaka, the Kawamura nō stage in Kyoto, and a temple in Kameoka. In December 1958, Sōfū suffered a stroke while painting a pine backdrop for a stage in Osaka—he recovered, but died of another stroke four years later.