Of all the incidents that struck the city of Edo and indeed Japan as a whole, the one that had greatest impact and changed the course of Japan’s history is considered to be the arrival of the "Black Ships" of Commodore Perry. Foreign vessels loomed near the coasts of Japan in the 18th century. In 1852 (the 6th year of Kaei era), Perry had embarked from the United States for Japan, in command of the East India Squadron consisting of four navy ships in search of a Japanese trade treaty and this was to sweep Japan into a whirl of chaos.

There is a famous ironic verse which goes “Awoken from sleep / of a peaceful quiet world / by Jokisen tea; / with only four cups of it / one can’t sleep even at night” (the four cups of Jokisen tea has a double entendre referring to the four black steam ships). The reason why people became panic-stricken is because this Perry's squadron appeared in the Uraga channel near Edo and there was a rumor that they would fire upon Edo. Various types of prints made by kawaraban (news broadsheets) became widespread among Edo residents.

The Tokugawa Shogunate was eventually compelled by Perry’s firm stance to conclude the Convention of Kanagawa (Nichibei Washin Jôyaku) and then the Japan-US Treaty of Amity and Friendship or Kanagawa Treaty (Kanagawa Jôyaku) in 1854 (the 1st year of Ansei era). Similar treaties were subsequently concluded with the United Kingdom (Anglo-Japanese Friendship Treaty), the Russians (Treaty of Shimoda), and the French (Treaty of Amity and Commerce between France and Japan), all of which opened up Japan bringing to an end the many years of Japan’s policy of national isolation. These five treaties are collectively called the "Ansei Five-Power Treaties" (Ansei Gokakoku Jôyaku).