Nankoku Hidai married Yasuko Yamamasu in 1948. Nankoku and Shoha (Yasuko) were well-known as a happily-married couple. They were both active in front rank of calligraphers and served as judges at Mainichi Shodo-ten (Mainichi Calligraphy Exhibition), and also at some other calligraphy exhibitions. Nankoku worked in the sphere of the avant-garde calligraphy and Shoha in the sphere of the mixed Kanji-Kana calligraphy. Their representations differed each other, but they had the common ardor and interest in calligraphy, and they both criticized their works.