Japanese scholars' selected translations of Chinese historical treatises Volume 10 Science and Technology

Author: Translated by: Du Shiren et al.
Editor-in-Chief: Liu Junwen
Publisher:
Publication Date: 1993-08-01
Features:
Fragment:
Jia Kui said: "Earlier, I submitted reports by Fu An and others using the Yellow River Degree method for measuring the positions of the sun and moon, which were quite accurate. However, the court historians consistently used the equinoctial degree method, which did not align with the sun and moon's positions. As a result, when measuring the positions of the sun and moon today, the discrepancy exceeds one degree, and they frequently report it as a variation. Although it is unclear when Fu An lived, the "Continuation of the Han Shu·Lüli Zhi" includes Jia Kui's discussion on calendars, which is generally believed to have been written around the fourth year of the Yongyuan era. Therefore, it can be considered that instruments similar to the Yellow River bronze instrument already existed by the fifteenth year of the Yongyuan era.
Facing Fu An's measurements of the positions along the Yellow River, as mentioned in the above quote, it seems that government officials specializing in observations, such as court historians, did not yet have (hutianyi) that could be used to measure the positions along the Yellow River. The creation of the "Taishi Yellow River Bronze Instrument" in the fifteenth year of the Yongyuan era is particularly noteworthy. Thus, it can be inferred that before the fifteenth year of the Yongyuan era, in addition to court historians, there were already (hutianyi) equipped with Yellow River rings in the world. In China, new astronomical observations and research were often carried out by non-specialized officials outside the court historians, and the above is one such example.
Jia Kui's discussion on calendars mentions Fu An, but it remains unclear whether (hutianyi) equipped with Yellow River rings existed before Fu An. For the pre-Qin period, let us set aside the discussion for now. According to tradition, the Han Dynasty had individuals who used (hutianyi), such as Luoxia Hong during Emperor Wu's reign and Geng Shouchang during Emperor Xuan's reign. However, the "Records of the Grand Historian·Lixu Zhi" and the "Han Shu·Lüli Zhi" only record Luoxia Hong as "calculating the calendar," without any explicit mention of him using (hutianyi).
In the "Fayan" written by Yang Xiong at the end of the Western Han Dynasty, it is stated: "Someone asked about the (hutianyi): 'It was designed by Luoxia Hong and measured by Xianyu Wangren, and modeled by Geng Zhongcheng.'" Another text, the "Records of the Jin Dynasty·Astronomical Zhi," which accepts this view, states in the "Instrumentation" section: "During the Taichu era of the Han Dynasty, Luoxia Hong, Xianyu Wangren, and Geng Shouchang created (hutianyi) to examine the calendar." Later, during Emperor Hedi's reign, Jia Kui further refined it and added the Yellow River ring.
As mentioned earlier, there are several doubts about the (hutianyi) created by Jia Kui. In the above quote from the "Records of the Jin Dynasty," the (hutianyi) created by Luoxia Hong, Xianyu Wangren, and Geng Shouchang are referred to as "" (yuan yi), where "" (yuan) is the same as "" (yuan, meaning round), and it can be understood as (hutianyi). However, in the above quote, all three are presented as having participated in the calendar reform during the Taichu era, whereas in reality, only Luoxia Hong was truly involved in the reform. After the calendar reform, until the third year of the Yuanfeng era (78 BC), someone opposed the new calendar. To clarify the issue, the chief calendar (shixie) Xianyu Wangren and others conducted observations, and the (hutianyi) is believed to have been created by Geng Shouchang in the second year of the Ganlu era (52 BC).
The "Continuation of the Han Shu·Lüli Zhi" states: "According to the report by Geng Shouchang, the chief of the Ministry of Agriculture in the second year of the Ganlu era, using the (hutianyi) to measure the paths of the sun and moon, he examined the state of the celestial movement. The sun passed one degree past Taurus and East Well, while the moon moved fifteen degrees. From there to Lou and Jiao, the sun moved one degree, and the moon moved thirteen degrees. This was due to the equinoctial degree, which was known to all in the world before this time." In the "Records of the Jin Dynasty·Astronomical Zhi," the (hutianyi) is referred to as "" (tú yi) here. Even if "" (tú yi) is also interpreted as (hutianyi), it remains unclear whether it was equipped with a Yellow River ring.
In the above quote, if everything up to "the moon moved thirteen degrees" is what Geng Shouchang said, then it can be said that his measurements were based solely on the equinoctial degree. As for Luoxia Hong and Xianyu Wangren, there is no definitive evidence to confirm the existence of a Yellow River ring during their time.
The above-mentioned "Continuation of the Han Shu·Lüli Zhi" includes the "Shishi Xingjing" (Stone Family Star Map), which states: "The Yellow River ring initially points to twenty degrees of the Dipper, twenty-five degrees away from the celestial pole, and twenty-one degrees on the equinoctial degree." Alongside the equinoctial degree values, it also provides the Yellow River degree values for the winter solstice sun's position. The winter solstice sun's position on the equinoctial degree is twenty-one degrees, which corresponds to around 70 BC. This value is then converted into the corresponding Yellow River degree value.