When FUJIWARA no Nakamaro's Revolt broke out in 764, the loyalist court faction dispatched envoys to close the barrier checkpoints in and out of Mino Province in an effort to prevent Nakamaro from raising more troops and to prevent his escape.
宝字8年（764年）に藤原仲麻呂が反乱を起こすと、朝廷側は仲麻呂の募兵と脱出を阻止するために美濃国に固関の使者を遣わした。