At first Kogurey is likely to use 'Kyung' as a unit of area influenced by the China's Kyungmoo System. It has not been well-known whether Kogurey's Kyung was equivalent to the China's, which had the same area and contents, or Japan's, in which only th ...
At first Kogurey is likely to use 'Kyung' as a unit of area influenced by the China's Kyungmoo System. It has not been well-known whether Kogurey's Kyung was equivalent to the China's, which had the same area and contents, or Japan's, in which only the term was used but it represented the totally-different unit of area. It is surmised to be a measure of Han's Chuck category. Afterward Kogurey invented a Chuck(35.6㎝) on its own and instituted one Bo that is equal to five Chucks. The Tanbo System, in which one Bo is five Chucks, was launched by setting up one Tan(250 Bos). In China, Tan was never used as a unit of area but as the meaning of district or precinct. But Tan in Kogurey was fixed as a term of some area, independent of China's Yangjun System.
The area of 250 Bos, 1 tan, was equal to 792.1㎡, and its shape might be a rectangle of 50 Bos x 5 Bos, or 25 Bos x 10 Bos. And its superior unit could be 2,500 Bos which is 10 times of tan. Its lower unit might be 1 Bos, 25 Bos(1 Bo x 25, or 5 Bos x 5 Bos). or 5 Bos(1 Bo x 5 Bos).
Kogurey's Tanbo System is likely to be enforced at the second half of the 4th century. Kan, instead of Bo, is used in this carved stone, and this signifies that Bo was employed as a unit of area. Japan, influenced by Kogurey, used Kan for 6 Chuck-length after the Tanbo System was established. Since the use of Kan means Bo was a unit of area, the Tanbo System had been already carried out in the middle of the 6th century. In the ancient Japan's Jungtanbo System, however, Kogurey's Chuck was used as a standard unit. Considering this, it is possible for Kogurey to have the Tanbo System, an independent Yangjun System, and also to institute a unit of measure on its own.
Considering improvement of the Yangjun System was deeply relevant to enforcement, the Tanbo System could come a long way. In Silla, the Yangjun System was first established under King Beopheung's reign. The Kyolbu System was instituted after Dang's systems and Chuck were introduced to Silla. Thus, the Tanbo System was settled down at the reign of King Sosurim(AD 373), when the law system was enforced and the Kogurey Chuck was rearranged.
The Kyolbu System as an original land surveying system began for the first time in the Silla Dynasty. The units of the system consisted of 'Pa,' 'Sok,' 'Bu,' and 'Kyol.' Pa, Sok and Bu originally designated the production in volume, but the Silla's system signified the size of a land in which harvested crops of one Pa, one Sok, and one Bu. As the agricultural productivity gradually improved, land surveying became highly demanded and the units, Pa, Sok, and Bu, were institutionalized by an ordinance in the early sixth century. The land is thought to be measured in the unit of Kogurye. On the other hand, Kyol was set as the unit of one hundred times of Bu regarless of production. The Kyol unit led to the Kyolbu system in the middle of the seventh century.
The area of one Kyol in the Silla Dynasty was fixed and used until the early Korye. At that time one Kyol represented bang(square) 33 bo(step), that is 1,089 bo. One Kyol, on the model of the Jyengjyen System of the Ju Dynasty, was equal to the size of one-ninth of 100 bo in every direction. The Silla adapted the Tangdaechyek, referring to 29.7㎝. As one bo was equal to 6 chyek, the area of one Kyol corresponded to 3458.1㎡.