While the city of Yokohama is a relatively recent phenomenon, the immediate area is a treasure chest of historical sites, including the Otsuka and Saikachido sites dating from the Yayoi Period (300BC - 300AD). Kamakura, which was the capital during the Kamakura Shogunate (1192 - 1333), has a plethora of ancient temples and historical sites as well as the Kanazawa Bunko library that was founded in 1275. The history of Yokohama itself, however, really started in the middle of the 19th century.

On July 8, 1853, a fleet of four American warships under the command of Commodore Matthew Perry arrived at Uraga, just south of Yokohama. Perry was carrying a letter from the President of the United States to the Emperor of Japan demanding that Japan open itself to international trade. After handing over the letter, Perry left Japan saying that he would be back one year later for an answer. Little did anyone realize that Perrys visit would lead to the elevation of an obscure fishing village on the southwestern coast of Tokyo Bay into the second largest city in Japan. But that is exactly the effect it had.

At the time of Perrys visit, Japan was under the control of the Tokugawa Shogunate, which had been established by Ieyasu Tokugawa after his victory in the Battle of Sekigahara in 1600. Leyasu established his capital at Edo (present day Tokyo) and Yokohama came under direct shogunal jurisdiction.

In 1636, the Shogunate introduced an edict forcing total isolation on the country. No one was allowed in (with the exception of a small group of Chinese and Dutch traders, who were confined to Dejima, an artificial island just off the coast from Nagasaki), and no one was allowed out. This policy was strictly enforced until Perry arrived. Although the Japanese were loathe to open up their country to foreigners and dangerous foreign influence, the sight of Perrys steam-driven warships, which the Japanese called Kurofune, or "Black Ships," startled them. They realized that they were technologically inferior to the Americans and that if it came to hostilities, they would be hard pushed to defend Edo against the powerful cannons on the American warships.

When Perry returned in 1854, the Japanese signed the Kanagawa Treaty opening two ports, Shimoda and Hakodate, to American ships. In 1858, the US-Japan Treaty of Amity was signed, opening up six ports to foreign trade, including Kanagawa. One year later, the trading rights for foreigners were transferred to Yokohama, a sleepy little fishing village at the time. Thus began the transformation that was to turn Yokohama into one of the most famous port cities in the world.