Details of this incident was as follows: when the Yoriyoshi's army returned to the Taga-jo Castle, his followers' camp was attacked by someone at night; Yoriyoshi requested the handing over of Sadato, a suspect of this incident.
これは、多賀城へ帰還中の頼義軍の部下の営所を何者かが夜襲したとされ、その嫌疑人として頼義が貞任の身柄を要求した事件である。