The term refers to a type of urban structures in Japan in which the city surrounds a feudal lord's castle. These cities did not necessarily form around castles after the Edo period; some are known as Jin'yamachi, cities that have evolved around Jin'ya or government offices that are not intended to provide military services. Defined broadly, Jokamachi includes Jin'yamachi. It is also referred to as Jōka as was common before the early modern period. History The advent of Jōkamachi dates back to the Sengoku period (period of warring states). Jokamachi functions both as a military base represented by the castle and an administrative and commercial city. Oda Nobunaga was the biggest contributor to the development of early-modern Jōkamachi. He aimed at promoting Heinobunri (distinguishing the samurai class from the rest by giving privileged status to samurai and disarming farmers and the rest) by forcing the samurai class to live in Jōkamachi, while establishing Rakuichi-rakuza (free markets and open guilds) to stimulate merchandising and trade. Jōkamachi flourished even more under Toyotomi Hideyoshi's regime, whose political and commercial epicenter Osaka-jōka became very prosperous as the center of commodities. Osaka continued to be the business center in the Edo period and was called the "kitchen of the land". Most of the world's walled cities comprise a castle and a city inside the defensive walls. While Japan did have towns and villages surrounded by moats and earth mounds such as Sakai and Jinaicho (temple town), Jokamachi initially had moats and walls only around the feudal lord's castle and did not build walls around the entire city. However, as Jokamachi developed and increased its economic and political value, it demanded protection from wars and turmoil. More and more cities were built with moats and defensive walls, the style of which is known as So-gamae (full defence perimeter), and gradually came to resemble walled cities. In the Edo period, Jokamachi served less as a military base and more as a political and economic capital for the Bakufu (government) and Han (domains). This shift was a result of the lack of warfare throughout the Edo period and the fact that most of the Han lords were occasionally transferred from one domain to another and thus had little attachment to the city per se (although crop yields remained matters of attention). Geographical locations that emphasized the castle's defensive abilities did not necessarily offer good access, and in many