• Journal of Korean Medical classics
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• v.31 no.2
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• pp.17-47
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• 2018

Objectives: The three nations of far Northeastern Asia, namely China, Korea, and Japan, have developed a tradition of Asian medicine within a common cultural realm. Studying Japan's Yunqi not only helps our understanding of Japanese traditional medicine, but the course of development taken by the three nations' traditional Asian medicine as a whole. Methods: All books relating to Yunqi published in Japan were studied, with special focus on books that are especially more important. Results: It is assumed that Japan's first book on Yunqi is 吉田宗桂's Ungiileonjib. The Japanese mainstream study on Yunqi is the annotations and studies on Suwenrushiyungilunao, written by Liuwenshu. YunQiLunAoKouYiis the first annotation on Suwenrushiyungilunao and had the greatest impact. Yunqilunjujie is an annotation book written by a Confucian scholar, and Yunqilunaoshuchao an annotation book composed by a Confucian doctor who was a thorough expert on sinology and the annotations ranged greatly from medical books, Confucian books, historical books and hundred schools of books. Aotouyunqilun is the most slight in terms of annotations compared to other annotation books, and Yunqilunaoyanjie is special in that it writes with both Chinese characters and Japanese language in order to help easier understanding by the novice scholars. Conclusions: Suwenrushiyunqilunao includes astronomy, geography, delivery sound, calendar, the eight trigrams, the Twelve laws, Shier chen, Constellation of twenty eight, Thirty-six birds, and secret days, which is leading to further study in these fields. Suwenrushiyunqilunao also contains excerpts from Suwen Liujiecangxianglun to describe the algorithm of the operation of Sun and Moon, which is also leading a further study in the field.

• Publications of The Korean Astronomical Society
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• v.36 no.3
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• pp.65-78
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• 2021

Jagyeokru, an automatic striking water clock described in the Sejong Sillok (Veritable Records of King Sejong) is essentially composed of a water quantity control device and a time-signal device, with the former controlling the amount or the flow rate of water and the latter automatically informing the time based on the former. What connects these two parts is a signal generating device or a power transmission device called the 'Jujeon' system, which includes a copper rod on the float and ball-racked scheduled plates. The copper products excavated under Gongpyeong-dong in Seoul include a lot of broken plate pieces and cylinder-like devices. If some plate pieces are put together, a large square plate with circular holes located in a zigzag can be completed, and at the upper right of it is carved 'the first scheduled plate (一箭).' Cylinder-like devices generally 3.8 cm in diameter are able to release a ball, and have a ginkgo leaf-like screen fixed on the inner axis and a bird-shaped hook of which the leg fixes another axis and the beak attaches to the leaf side. The lateral view of this cylinder-like device appears like a trapezoid and mounts an iron ball. The function of releasing a ball agrees with the description of Borugak Pavilion, where Jagyeokru was installed, written by Kim Don (1385 ~ 1440). The other accounts of Borugak Pavilion's and Heumgyeonggak Pavilion's water clocks describe these copper plates and ball releasing devices as the 'Jujeon' system. According to the description of Borugak Pavilion, a square wooden column has copper plates on the left and right sides the same height as the column, and the left copper plate has 12 drilled holes to keep the time of a 12 double-hours. Meanwhile, the right plate has 25 holes which represent seasonal night 5-hours (Kyeong) and their 5-subhours (Jeom), not 12 hours. There are 11 scheduled plates for seasonal night 5-hours made with copper, which are made to be attached or detached as the season. In accordance with Nujutongui (manual for the operation of the yardstick for the clepsydra), the first scheduled plate for the night is used from the winter solstice (冬至) to 2 days after Daehan (大寒), and from 4 days before Soseol (小雪) to a day before the winter solstice. Besides the first scheduled plate, we confirm discovering a third scheduled plate and a sixth scheduled plate among the excavated copper materials based on the spacing between holes. On the other hand, the width of the scheduled plate is different for these artifacts, measured as 144 mm compared to the description of the Borugak Pavilion, which is recorded as 51 mm. From this perspective, they may be the scheduled plates for the Heumgyeonggak Ongru made in 1438 (or 1554) or for the new Fortress Pavilion installed in Changdeokgung palace completed in 1536 (the 31^st year of the reign of King Jungjong) in the early Joseon dynasty. This study presents the concept of the scheduled plates described in the literature, including their new operating mechanism. In addition, a detailed model of 11 scheduled plates is designed from the records and on the excavated relics. It is expected that this study will aid in efforts to restore and reconstruct the automatic water clocks of the early Joseon dynasty.