It is well known that the intrusions of the western powers in the 1850's helped trigger the eventual collapse of the Tokugawa Shogun's. In particular, it was the Black Ships of the United States in 1853 commanded by Commodore Perry.
In a carefully calculated act of intimidation, Perry led a squadron of four warships into Edo Bay. Perry's command ship was a state-of-the-art steamship. At more then 2,400 tons, it overmatched at least 15 Japanese ships put together. The American ships entered Edo Bay at nearly nine knots, leaving the shogunal navy scrambling in their wake.
Shogunal officials were astonished by the ships' armaments. Observing from shore, Kagawa Eizaemon, an aide to the Uraga magistrate, counted about seventy large-caliber cannons. The shogunate had roughly 100 cannons around Edo Bay, but only 11 of these were of comparible caliber.
With four ships Perry had outgunned Japan's supreme warlord. Stunned, shogunal forces were forced to receive President Fillmore's "request" for a treaty with the United States. Perry had "invaded" Japan without firing a shot.