In 1867, he held the Shiko-kaigi (four major lords' meeting) with Hisamitsu SHIMAZU, Toyoshige YAMAUCHI, who was the former lord of the Tosa Domain, and Munenari DATE, who was the lord of the Uwajima DomainE to discuss punishment on the Emperor's enemy, the Choshu Domain, which resulted in the twice Choshu conquest although Shungaku opposed it.
慶応3年（1867年）には、島津久光や前土佐藩主の山内豊信（容堂）、宇和島藩主・伊達宗城らと四侯会議を開き、朝敵となった長州の処分について話し合い、春嶽は長州征伐には反対するが、2次に渡る長州征伐に至る。