In 1859, the village of Yokohama became a treaty port under pressure from the United States. Yokohama would serve as an international port to the Kanagawa juku, one of the 53 stations of Tōkaidō (highway linking Edo to Kyōto). The Tokugawa government demarcated the foreign concession by a canal around Yokohama, the Yoshida River serving as a natural boundary between Kanagawa and Yokohama. Checkpoints, known as Kanmon (関門), were installed at each bridge over the canal and the Yoshida River. The area enclosed within these gates became known as Kannai, "within the gates".
The principal purpose of these checkpoints was to prevent contact between samurais and foreigners, for fear that the samurai would acquire "dangerous" knowledge from the West which could jeopardize the shogunate. Eventually, a number of samurai did get the inspiration from the West to topple the established order and seek to modernize Japan. The samurai revolt culminated with the abolition of the shogunate and the Meiji Restoration.
Nowadays Kannai has become Yokohama's administrative district. Most of the grand European-style buildings were destroyed in the Great Kantō Earthquake of 1923. Those that survived or were rebuilt are located along Minato-ōdōri Avenue and Honchō-dōri Avenue. The most remarkable are the Customs House, the former headquarters of the Yokohama Bank (built in 1904), the Neo-Renaissance Port Opening Memorial Hall (built in 1918), the German-Renaissance Kanagawa prefectural museum of cultural history (erected in 1904), and the Yokohama Archives of History.
Chinatown & Yamashita Park
Founded in 1863, Yokohama's Chinatown ("chukagai" in Japanese) is the largest in Japan. It is a must on anyone's list of culinary destinations. If you are going to have Chinese food in Japan, this is where you should try it. It usually squirms with tourists who have come to taste the Chinese delicacies, buy traditional Chinese art or gape at the colourful and intricately decorated Chinese architecture. With 18 million annual (mostly Japanese) tourists passing through its streets, Chinatown is the most popular attraction in Yokohama (food being the main focus, its power of attraction on the Japanese population cannot be underestimated). As for the actual sights, the only true attraction in its own is the extravagantly gilded Kantei-byō Temple (関帝廟), dedicated to Guan Yu, a Han-dynasty general deified as a protector of the Buddhist dharma.
Just north of Chinatown, you will find the Yamashita-kōen Park, with the Marine Tower (the tallest inland lighthouse in the world), the NYK Maritime Museum, and the Hikawa-maru moored at the Sea Bass Pier.
Map of attractions in Yokohama