黑船來航
In 1853, in the aftermath of the Perry Expedition to demand an end to Japan's national isolation policy, at first Yoshinaga joined anti-foreigner party led by Tokugawa Nariaki ( "daimyō" of Mito Domain) and Shimazu Nariakira ( "daimyō" of Satsuma Domain). However, later he changed his position to opening the country to foreign trading party after contact with "rōjū" Abe Masahiro.