Kyoen Kankan (the wood strip on which ancient Chinese characters are written) (居延漢簡)

Kyoen Kankan is mokkan (a narrow strip of wood on which an official message is written) of the Former Han and the Later Han periods, discovered in the Kyoen Hosui site covering from Ejin Banner of Inner Mongolia, China to the northeastern region of Jiuquan City, Gansu Province, China. Not only are they valuable as historical materials, but they are also prized as penmanship.

History of discovery
The expedition of the western regions of China centering on Dunhuang City and Tibet as well as the excavation and research of sites were conducted by many explorers in the Chinese continent since the end of the 19th century.

Sven Hedin (Swedish geographer) who was one of these explorers often organized an expedition to conduct investigation since around 1899 and had a track record of discovering mokkans and so on in large amount. The ages of mokkans ranged from the Former Han period to the Wei-Jin-Nanbeichao period, but the amount was not more than several hundreds.

In the meantime, 'The Sino-Swedish Expedition', a collaboration of Sweden and China, under the leadership of Sven Hedin was dispatched to the western regions of China in 1930. The expedition was excavating the site of Boro (watch tower) while crossing the Gobi Desert and at that time mokkans of the Han period were discovered. Since then mokkans have been continuously discovered one after another, and as a result of the research conducted over the following year 1931, approximately 10,000 mokkans were found; this is an unprecedented number for those which belonged only to the Han period. The discoverer is Folke Bergman, a Swedish archaeologist. The general name of these mokkans is 'Kyoen Kankan'.

Age and content
The ages of Kyoen Kankan were all in the Han period and it ranges from the period when the Emperor Wu (Han) of the Former Han established Kyoen Prefecture to the middle of the Later Han period. Specifically, the oldest one was used in B.C. 102 and the latest one in 98.

Many of its contents were official documents and especially most of them were the records of stationing by Choekigun Kyoen Toi (The chief of Kyoen of Choeki County) and Kensui Toi (The chief of Kensui) who guarded the area, but some of them included law, medical books, calendar and so on of the time.

Historical assessment
Kyoen Kankan was highly valued as a primary historical material which revealed the actual state of administration of the western region in the Han period.

The key factor is that most of the contents were the records of stationing. That region was an outlying area and it was always exposed to the threat of different ethnic groups around the region. It was therefore the militarily important area and the fact that the records remained will directly indicate all of administration of the western region of the time.

All of transliterated documents and the study of these documents were published as "Interpretation of Kyoen Kankan" by LAO Kan in 1943. After the war, "Kyoen Kankan Kohen" (The first volume of Kyoen Kankan) was published by the archaeology research institute of Chinese Academy of Sciences in 1957 and "Kyoen Kankan Kootsuhen" (The 2nd volume of Kyoen Kankan) by Institute of Archaeology of Chinese Academy of Social Sciences in 1980.

In addition, the excavation and investigation been continued in parallel, and Kyoen archaeological team started to re-examine the Ejin river area in 1972 and more than 20,000 mokkans have been discovered since 1973 (Kyoen Shinkan).

Calligraphic assessment
Kyoen Kankan led to a great discovery in the world of Shodo (calligraphy) as well. The days when Kyoen Kankan was written correspond to the period when the calligraphic style changed from tensho (seal script) to reisho (clerical script), but very few Kinsekibun (words written on metal or stones) such as stone monuments remained when such change, i.e. reihen (change in calligraphic style), occurred in the Former Han period and therefore reihen was only presumed on the basis of a very small number of penmanship.

However, all the possible calligraphic styles of the transitional period in those days were used in Kyoen Kankan: from pure tensho (seal script), through 'korei' (old clerical script) which was early reisho (close to reisho) to reisho with complete hataku (horizontal lines ending in a noticeable triangular tail that were specific to reisho) which is called Happunrei; thereby the process of reihen was revealed.

Until then, reihen was thought to occur in a linear manner: tensho, korei to happunrei.

However, because korei and happunrei coexisted in Kyoen Kankan in almost the same period, it was concluded that happunrei was originally one calligraphic style of reisho and it became the standard later in lieu of shoho (penmanship, calligraphy) of korei.

In addition to its value in calligraphy history, its simple calligraphic style created by common people became popular as penmanship and now people often copy it as the work of calligraphy or imitate its calligraphic style. It is creating a genre as mokkan-sho (calligraphic style of mokkan).