Yoshitada's uncle, MINAMOTO no Yoshimitsu, who was displeased with Yoshitada's leadership and aspired to replace him as leader of Kawachi-Genji, arranged an attack on him through his retainer, TAIRA no Narimoto.
義忠の叔父の源義光は義忠の権勢が高まるのに不満を感じ、自らが河内源氏の棟梁になることを望み、家人平成幹に義忠を襲わせた。