According to 'Uesugi-ke Gonenpu (Chronological list of the main events of the Uesugi family),' the birth of Sadakatsu was immediately notified to Kagekatsu who was staying in Fushimi at the time, and all the retainers in Fushimi visited the lord to offer their congratulations.
「上杉家御年譜」によれば、定勝の誕生は直ちに当時景勝が滞在中であった伏見に伝えられ、伏見在中の家臣たちは悉く参賀し慶祝したと記録されている。