Jobosei (a city plan where streets were laidout in a grid pattern) (条坊制)
Jobosei was the city plan seen in cities that contained the Emperor's palace in countries such as China, the Korean Peninsula, and Japan; furthermore, the Suzaku-oji Street was placed in the center of the city running from east to west. The Jobosei-type city was built in a symmetrical and square shape and streets were organized so that the Oji (jo) streets that ran south to north and the Oji (bo) streets that ran east to west were arranged in a grit pattern.
The Scripture of Confucianism, "Shurai" (Rites of Zhou) has descriptions about the capital where the emperor's palace is placed as follows.
The capital was built in a square shape with the sides 36 kilograms long and with each side having three gates.'
In the capital city, nine streets running east to west and nine streets running north to south were arranged in the grid pattern; moreover, the width of each street was set to be nine times that of a rut (242.4 centimeters).'
The Imperial palace was placed at the center of the city, a shrine (Sobyo) for the worship of ancestral spirits was placed to the east of the palace, and a shrine (Shashoku) for the worship of the gods to protect the land was placed to west of the palace.'
The Imperial Court was placed in the front, located at the south side, and markets were placed in the back, located at the north side.'
The Jobosei-type capital was developed in China based on this concept. It is thought that Jobosei was later introduced to the Korean peninsula and Japan as the Shurai idea was spreading and Jobosei-type capitals were being developed in these countries.
Examples of Jobosei in each country
Jobosei, as well as Fusui-setsu (feng shui theory) (Shijin-soo [an ideal topography for the four Taoist gods, with a river in the east, a broad avenue in the west, a basin in the south, and a hill in the north]), was a basic idea of constructing capitals in China, however, construction of cities based on Jobosei became unpopular with the beginning the Sung Dynasty period.
It is said that Jobosei was applied in the capital city of Silla around the late seventh century in the Korean Peninsula.
The Jobosei-type cities in Japan includes capital cities such as Fujiwara-kyo (the Fujiwara Palace; the ancient capital of Fujiwara), Heijo-kyo (the ancient capital of Japan in current Nara), Nagaoka-kyo (the ancient capital of Nagaoka), and Heian-kyo (the ancient capital of Japan in current Kyoto), and Dazaifu, Taga-jo Castle and others which controlled a broad area. However, walls were not constructed around the capital cities in Japan because invasion by other races was not considered a threat because Japan was an island (Dazaifu might have been built with walls), although a castle with outer bailey (a capital surrounded by walls) was seen in the continent where invasion by different races was feared. Only Rajo-mon Gates seen in Heijo-kyo and Heian-kyo, ancient capitals of Japan in current Nara and Kyoto, respectively, were located at the Suzaku-Oji Street to indicate the entrance to the capital cities.