Nankoku understood Tenrai’s maxim that an artist had to make a living from a different job in order to pursue his own art independently. In 1948, he married Yasuko Yamamasu (artist name, Shoha) and quitted the job of Kokudo-Chiri-In. He moved to Yokohama and established Yokohama Seihan Kenkyujo (Yokohama Precision Plate-Making Company),which was the plate-making business putting his technical skill in printing and phototype process to use. The start was the opportunity that he bought a valuable glass-screen from his teacher of Tokyo Koto Kogei Gakko ( now Chiba University). He started to print on silk at first, but the business was in a difficult start.
In 1965, after returning from the United States and Europe, Nankoku realized keenly the necessity of education of calligraphy, and planned to restart publishing by Shogakuin. While he prepared for reopening publication, he was faced with the technical improvement of Yokohama Seihan Kenkyujo and he devoted all his energies to improve the printing precision. In 1967, after finally recovering business, he held a one-man-show after a long time.
The first issuance of reopened Shogakuin Publications (inactive since1944) was the restration of Tenrai’s ‘Syusaku-jo (study books)‘, in 1969. Nankoku handwrote the print dots himself to improve the poor printing version before the war, and thus he realized the clear and impressive printing which conveyed Tenrai’s Sho correctly and vividly. He republished Tenrai’s long-waited works, and the old rare Japanese and Chinese calligraphy books.(The twenty-volume Gakusho Sentei of Tenrai, eight-volume Chinese calligraphy book Yoseisai Jo and several other books were published).
While he concentrated on his activities of Shogakuin Publications, he made fifth and sixth tour of the U.S. and taught at University of California Extension, San Francisco. From 1974 to 1975, Nankoku helped establish ‘Tenrai Kinenkan (Tenrai Memorial Museum)’ at Tenrai’s native place, Mochiduki-machi in Nagano prefecture. From 1977 to 1978, he toured the U.S. And he studied over 10,000 pieces of the ancient stone rubbings of Chinese calligraphy, formerly owned by the Mitsui Bunko, at the East Asiatic Library of the University of California Berkeley.