Naoya SHIGA's grandfather, Naomichi SHIGA, served as a butler of the Soma Clan, the lord of the former Soma- Nakamura Domain; he developed Ashio Copper Mine together with Ichibe FURUKAWA, the founder of Furukawa Zaibatsu, and was involved in the Soma Incident.
志賀直哉の祖父・直道は、旧相馬中村藩主相馬氏の家令を勤め、古河財閥創始者古河市兵衛と共に足尾銅山の開発をし、相馬事件にも係わった。