Yokohama's population of 3.7 million makes it Japan's largest incorporated city. Yokohama developed rapidly as Japan's prominent port city following the end of Japan's relative isolation in the mid-19th century, and is today one of its major ports along with Kobe, Osaka, Nagoya, Hakata, Tokyo, and Chiba.
The Yokohama is a breed of chicken that originated from Japanese breeds. Yokohama is not where the breed originated, but it is the port where a French Missionary named Girad first exported the breed to Europe where further breeding would create the Yokohama known today.
It was developed from two different Japanese Natural Monument breeds, the principal progenitor is the Minohiki or "Saddle Dragger". Some percentage of the ancestral founders were probably another Japanese treasure called the Onagadori, but it is likely that at the time of the founders' introduction to Europe, the lesser known Minohiki was simply not as highly celebrated as the Onagadori. Consequently, many Minohiki were likely confused with Onagadori. Regardless of which of these important breeds were more significant in the development of this unique fowl, the ancestors of today's Yokohama were imported from Yokohama, Japan. In appearance, it most closely resembles the Minohiki breed, and to a lesser extent to the European Phoenix Breed, which probably shares many of the same ancestors. The European Phoenix however, has more Onagadori and less Minohiki in its genetic makeup, whilst the opposite is true for the Yokohama Fowl. The Black Sumatran Fowl is a close relative of the Minohiki and Yokohama.