In April 16, 1017, an incident occurred where the roto (retainer) and one party of HADA no Ujimoto killed KIYAHARA no Munenobu (Sei Shonagon's elder brother) in the capital, however, it was later found that the incident was ordered by Yorichika.
寛仁元年（1017年）3月11日(旧暦)、京中において郎等・秦氏元の一党が清原致信（清少納言の兄）を殺害する事件が起こるが、後にこれが頼親の指示であったことが判明する。