Harumi and Shichisei Shiyo (七政四余)

－　OKANOI Gentei(岡野井 玄貞) learned astrology(七政四余) from Razan（螺山） －

In the SHIBUKAWA Harumi's biography (春海先生実記, Harumi sensei Jikki in Japanese), OKANOI Gentei(岡野井 玄貞), one of the Harumi's teachers of Shoushi-li(授時暦), received the teaching of 七政四余 (Shichiseii Shiyo in Japanese) from Razan (螺山) who came to Japan in 1643 as a member of the mission to Shogun from Chosun (Korea). For this reason, there is interpretation that “Shichisei Shiyo” is considered as the kind of method to calculate planetary calendar and Shoushi-li(授時暦) was brought to Japan by Razan. 　However, this is a misunderstanding based on presumption without evidence. Shichisei Shiyo means 7 heavenly bodies (Sun, Moon and 5 planets) and 4 imaginal planets (ascending node, descending node, distant point of the moon and unknow one). However, Shoushi-li has no calculation method for Shiyo (4 imaginal planets). Therefore, Shichisei Shiyo was not a Shoushi-li. In addition to that, other Harumi's teachers MATSUDA Syoujyun (松田承順), Nakamura Keisai (中村惕斎), and IKEDA Masaoki (池田昌意) also had a knowledge of Shoushi-li(授時暦). SHIMADA Sadatsugu (島田貞継) and ANDO Arimasu (安藤有益), who are retainer of Aizu, completed the first version of revised calendar based on Shoushi-li(授時暦) in the calendar reform team with Harumi. Therefore, there is no possibility that Shoushi-li(授時暦) was spread to these people via Razan - Okanoi route. 　In Jinkiroku (壬癸録) whichi is an oral record of Harumi compiled by Harumi's disciple TANI Jinzan, there is clear description that Astrology which the profits and losses will be forecasted by Shichiyou Shiyo(七曜四余), and Harumi himself stated that OKANOI had learned this technique from a Korean and he had been very familiar with it. This Korean is considered as Razan(螺山). Shichiyou and Shichisei are same meaning. As an evidence, there is a sheet of horoscope of a person who born in 1706/01/01 based on Shichisei Shiyo in the Shibukawa family’s document. Therefore, Shichisei Shiyo learned by OKANOI from Razan was not a calendar system, but an Astrology, and Harumi also studied it. The reason why Harumi revitalized the planetary calendar including the Shiyo which is not practical, seems to be influenced by Astrology(七政四余).