However, when he knew that the western camp, including his father, suffered a crushing defeat from the attack by the eastern camp and fell apart to pieces at the main battle of the Battle of Sekigahara, he escaped from Osaka-jo Castle behind the scenes with the help of a senior vassal, Jinnai TSUYAMA and his menoto (a woman providing breast-feed to a highborn baby), etc. into Jusho-in Temple, a subtemple of Myoshin-ji Temple in Kyoto, and became a priest by the chief priest, Eryo HAKUHO and entered the Buddhist priesthood.
しかし、関ヶ原本戦で父をはじめとする西軍が東軍に大敗して壊滅したことを知ると、重臣の津山甚内や乳母などの手によって密かに大坂城から抜け出して京都妙心寺の塔頭寿聖院に入り、住職である伯蒲恵稜の手によって出家し、仏門に入った。