Emperor Uda mentioned in "Kampyo-Goyuikai"/"Kampyo-no-Goyuikai (a group of precepts for governing)" that he was greatly shocked by the death of Udaijin, MINAMOTO no Yoshiari, which could have been one of the reasons he left the throne.
また『寛平御遺誡』には右大臣源能有の死による強い衝撃について書かれており、退位と結びつける見方もある。