According to "Okagami" (literally, the Great Mirror; a historical tale), the circumstances behind that is as follows; Korechika had had audiences with Emperor Ichijo through his younger sister, the Emperor's favorite chugu, with which Higashi Sanjoin (FUJIWARA no Akiko) had been displeased, and finally forced her way into the Emperor's residence at night and begged the hesitating Emperor in tears to give a senji to Michinaga.
この辺りの子細について、『大鏡』は、伊周が一条天皇の寵愛深い妹の中宮を介し、御意を得ているのをかねてから快からず思っていた東三条院が、夜の御殿に押し入り、渋る一条天皇を泣いて説得したとする。