One theory has it that although Yukinaga was basically an educated person, he failed to recall two of the seven virtues described in the dance music named 'Dance of the Seven Virtues' which had followed the seven virtues of the military arts of Emperor Taiso of Tang (Tang Taizong,) thereby being scornfully nicknamed the 'Young man of the Five Virtues,' and therefore he became thoroughly tired of this world and retired to live in seclusion.
行長は本来は学識ある人物だったが、唐の太宗の武の七徳に基づく舞曲「七徳の舞」の内の二つの徳を忘れたことから「五徳の冠者」と渾名され、世間に嫌気がさして遁世したという説がある。