In 1862, he attempted to assassinate a foreign minister in Kanazawa, Musashi Province with his fellow members including Takasugi, but the scheme was known to the heir of the lord of the domain, Sadahiro MORI, in advance and was not put into practice, and then the members were ordered confinement to the hantei.
文久2年（1862年）、高杉ら同志と武州金澤（金沢八景）で外国公使を刺殺しようとしたが、計画が事前に藩主世子の毛利定広に伝わったため実行に到らず、謹慎を命ぜられる。