According to "Uesugi Nenpu" (Uesugi's chronological record), it was a marriage ordered by the bakufu (Japanese feudal government headed by a shogun): 'On April 7, 1658, Hyobu CHISAKA told (Tsunakatsu) that he had been ordered to marry Sanhime to Kozuke no Suke KIRA by Masayuki HOSHINA in front of the assembled company such as the roju (senior councilor) Tadakiyo SAKAI, Nobutsuna MATSUDAIRA and Tadaaki ABE.
『上杉年譜』は「万治元年3月5日、柳営において老中酒井忠清・松平信綱・阿部忠秋列座のなか、保科正之から三姫を吉良上野介へ嫁がせるべき旨を命じられたことを千坂兵部が（綱勝に）言上した」と幕命による婚儀と記している。