The reasons were attributed to Nagayasu NARITA bowing without dismounting from a horse while warlords usually bowed after dismounting from a horse, the Narita clan descended from the Fujiwara clan, a family lineage which was given permission to bow without dismounting to the likes of, MINAMOTO no Yoshiie, the head of the samurai (warrior) families.
原因は諸将が下馬拝跪する中、成田長泰のみが馬上から会釈をしたためであったが、成田氏は藤原氏の流れをくむ名家で、武家棟梁の源義家にも馬上から会釈を許された家柄であった。