The shogunate was wary of Russia's southward expansion policy. "Ezo (Hokkaido)" had been facing a crisis since the end of the Edo period.

Seeking an ice-free port, Russia is forcing its way south whenever possible. The invasion of Ukraine has been criticized around the world, and there are voices saying, "Japan is not immune to this!" Those who sneer at this and call it an exaggeration are probably in the minority now. In fact, in Japan during the Edo period (the end of the Tokugawa shogunate), Russia's southward policy was seriously considered, and a facility was actually built. …