User:00101984hjw/Korean Calendar Conversion

A Quick Introduction

Throughout its many years of history, Korea has used various calendar systems since the Korean Three Kingdoms Period (see [1] for quick reference).

During the early Goryeo period, the Tang-made Xuanming calendar (선명력; 宣明曆) was used until 1281. While the Tang revised the Xuanming calendar several times Korea insisted on using an unmodified version until Munjong's reign, when several improvised calendars, such as the Sipjŏng (십정력; 十精曆), Chilyo (칠요력;七曜曆), Kyŏnhaeng (견행력;見行曆), Tungap (둔갑력; 遁甲曆), and Taeil (태일력; 太一曆) calendars were created.

In 1281 (the 7th year of Chungnyeol's reign) the Yuan-made Shòushí calendar (수시력; 授時曆) was adopted. However, Goryeo scholars tended to stick with the obsolete Xuanming calendar, which they were more accustomed to. During the late Goryeo period a revised version of Shòushí, known as the Taet'ong (Dàtǒng?) calendar (대통력; 大統曆) saw limited use.

Shòushí continued as the standard calendar until early Joseon when the Ch'iljŏngsan (칠정산; 七政算) was created to serve as the first Korea-specialized calendar system during the reign of Sejong the Great. The Ch'iljŏngsan consisted of two books, the Ch'iljŏngsannaep'yŏn (칠정산내편; 七政算內篇) which detailed methods to accurately calculate dates and celestial movements regarding Korea's geographic location based on the Shòushí calendar, and the Ch'iljŏngsanoep'yŏn (칠정산외편;七政算 外篇), which was based on the Huihui Lifa.

Beginning in 1644 (22nd year of Injo's reign), Korean scholars began discussing the adaptation of the Qing-made Chongzhen calendar, as the limitations of the Ch'iljŏngsan became clear. Although the Chongzhen calendar was officially adopted in 1653 (4th year of Hyojong's reign), it was not implemented in earnest until 1725 (1st year of Yeongjo's reign) as Korean scholars had little knowledge of western astronomy (which heavily influenced the Chongzhen calendar) and the Qing were reluctant to reveal any information of their new innovation.

The Gregorian calendar was adopted on January 1, 1895.

Why it matters

Per MOS:JG, dates on the English Wikipedia must be in Julian or Gregorian calendar. However, due to the lack of secondary sources, many articles on relatively obscure historical Korean figures must rely on primary sources for references (most commonly the Veritable Records), which predominantly use a lunisolar calendar system. Furthermore, Korean-language secondary sources often do not clarify whether the date used is in Gregorian. While there are tools available online for the conversion of Korean lunisolar to Gregorian ([2], [3]), these tools are more than likely based on the Chongzhen calendar, the current lunar (lunisolar) calendar system used in Korea. This means that dates written on historical records published before the 18th century should probably not be converted using these tools if accuracy is to be kept precise.

The problem is, as the current Korean-speaking community on the enwiki is pretty small, and English-language publications on Korean history are relatively scarce, not much discussion has been made on specific guidelines on historical dates. This problem is even more prevalent on the kowiki, where lunisolar dates are ubiquitous throughout history articles. There are probably a whole ton of unsourced, unconverted dates in articles about pre-1895 Korean history at the moment (see Wikipedia talk:WikiProject Korea/Reliable sources/Archive 2#Dates used by EKS).

Thankfully, conversion tools are widely available for Chinese calendar systems[4](although a conversion template is yet to be made). The problem is most editors don't know which source uses which. If robust guidelines are to be made on this issue an ideal subpage may be necessary to classify all the sources into lists depending on what calendar system they use.

Calendar-specific guidelines

In addition to WP:PRIMARY, secondary sources are preferred over primary sources due to this issue.

Chongzhen / Siheon

For primary sources from works published in Korea between the 20th century and the 18th century dates may be in the Chongzhen lunisolar calendar. As the Chongzhen calendar is the current lunisolar calendar used in Korea online converter tools may provide an accurate conversion ([5], [6]).