It was customarily accepted by the warrior families that 'the families that could rise to Shogun, leader of the samurai, were limited to those extending from the Seiwa Genji.'
「武家の棟梁となる将軍に就く家柄は、清和源氏に連なる家系に限る」という認識が武家の間でまことしやかに慣例となっていた。