Kogyu (Yoshio) had close relations with Ryotaku MAENO and Genpaku SUGITA among others, and praised their achievements by contributing a foreword for their book "Kaitai Shinsho" (New Book of Anatomy).
中でも前野良沢・杉田玄白らとの交流は深く、2人が携わった『解体新書』に耕牛は序文を寄せ、両者の功労を賞賛している。