In the Jokyu War (1221), Soncho played an important role as Retired Emperor Gotoba's man and took charge of capture and detention of Kintsune SAIONJI and his son, who were considered leaders of the pro-Kamakura bakufu group, although Kintsune was Soncho's brother-in-law.
承久3年（1221年）の承久の乱に当たっては、義兄弟ながら親幕府派の筆頭と目されていた西園寺公経父子の逮捕・監禁に当たるなど、上皇の片腕として行動する。