So the story starts here, and it goes like this.
When I lived in Sendai in 2005, I lived in a neighborhood astride Japan National Route 4, the old Ōshū Highway.
This was the trunk road used by the 8th century Yamato state in its colonization of Emishi lands in northern Honshu. Later, it was the highway by which commerce, mail, and daimyo processions moved up and down the region. Today, it's still a major trunk road, but around my house, there was plenty of sidewalk, and lots of businesses, so I often went out exploring.
Right next to a Porsche dealership, a sign pointed down a narrow alley, reading Yamanotera Dōun-ji. Intrigued to find a new to me temple, I stepped into the alley, following as it slowly narrowed. When it opened back up, what I found left me breathless.
I remember trees. A meadow, slowly rising. Temple buildings on the far side of the meadow. And no sound of a nearby major national highway at all.
So I kept walking. Don't misunderstand me-- I'm not punching up the Miyazaki factor here or anything. It really was a stark difference, night and day, between the ambiance of the road and that of the the meadow before the temple complex. I remember caves in the rock face to the left-- apparently in those caves is the Iwaya Kannon temple and the Byakko Kannon temple. On analysis of a map today, I can see that those, too, were smaller temples and hermitages of their own. But at the time, I was just standing there staggering forward with my mouth agape at how suddenly peaceful it was. Up the little rise toward a copse of trees, I looked left and right trying to get my bearings, when I tripped on unexpectedly stony ground. As I got up, I realized I'd fallen on ground in front of a grave. To the right, a wooden stake, painted white, had an inscription in black letters. Sendai-han Tenmongakusha Ōtsuka Yorimitsu-sensei no Haka. Grave of Sendai domain Astronomer, Ōtsuka Yorimitsu-sensei.
And that, dear listener, is how I literally stumbled on history one day when I'd gone out for a stroll.
Much later, I learned that this temple-- a temple of the Sōtō sect-- was founded in the early 8th century. It's one of the oldest in town, and at this point it has existed for longer than province that used to be here until 1869. But who was Ōtsuka Yorimitsu, the astronomer buried at Dōun-ji temple?
Ōtsuka Yorimitsu was an 18th century astronomer. He was a Sendai vassal, born Kyoho 17 (1732), and he's also known as Ōtsuka Zen'emon. He studied under astronomer and mathematician Satake Yoshine (1689-1767), and was licensed by Satake in 1760. Ōtsuka served two generations of daimyo, Date Munemura (1718-1756, r. 1743-1756) and his son Date Shigemura (1742-1796, r. 1759-1790), both of whom showed great interest in his work. Ōtsuka made celestial observations from around Sendai including from the meadow outside the venerable Dōun-ji-- in those days, this would've been some distance outside the Sendai castle town, and thus quieter and less likely to have the modest extent of light pollution that would've existed at the time.
At the time, there was a new lunisolar calendar system called the Hōryaku calendar, which was introduced in 1755. The Shogunate, during the reign of reformist 8th shogun Yoshimune, was aiming for its own new calendar based on the influences of western astronomy, a project spearheaded by Nishikawa Seikyu. But Nishikawa did not finish his task before Yoshimune's death in 1751. Meanwhile, the Tsuchimikado family in Kyoto, a line of hereditary onmyōdō diviners who headed the imperial court's Ministry of Divination-- the subject of a very popular Friday Night History thread before we made the jump to podcast format-- clashed with Nishikawa, and eventually won out. Making a calendar was a part of the ministry's work, because in order to ensure the proper conduct of rites, you need a proper calendar so that you know what stars are in what places. Thus, the Ministry was also like western alchemists, in that it needed to deal with real science. It had a hand in astronomy, weather forecasting, telling time, making official calendars-- this is all important to the magic *and* the court ritual. Things need to be done *properly,* between all the different planes of existence. For over a *millennium*, through the highs and lows of imperial court power, the Ministry handled all of this. The trouble was, despite all of this, the Hōryaku calendar-- based on the earlier Jokyo calendar-- had flaws, and Tsuchimikado had used the essentials of the Jokyo calendar unaltered. And on October 7, 1763-- 1st of the 9th month of Hōreki 13-- there was an eclipse that the calendar missed entirely. Ōtsuka was one of several astronomers from Sendai domain that predicted the eclipse despite this error-- and one of quite a few across the country. Bear in mind that speaking out too stridently had a way of getting scholars in trouble-- we talked recently about Hayashi Shihei, and his discourse on coast defense and how it ran afoul of the Shogunate. But in this case, Ōtsuka was not alone in voicing this criticism, and in the end, the Hōryaku calendar was retired from use in 1798, after only 43 years in service. Given the importance of calendars to the conduct of rites, I can see how he got away with it.
A later Japanese calendar from 1867. (Image in PD)
But Ōtsuka's career wasn't only focused on astronomy-- he was also an educator who worked with the Date clan's main domain school. You might remember our earlier episode about Kōtōdai Park and Yōkendō, the Sendai domain school. Yōkendō's school library was partially housed some distance away from the school's main campus in Hachiman-chō, at Ryūhō-ji temple; this was where the school kept its outstanding collection of religious texts and Chinese classics among others; Louise Watanabe Tung's article "Library Development in Japan" notes that this library-- one of several in Sendai-- had 16,433 volumes in its collection, and predated Yōkendō by a few decades. In another note of direct personal experience, as it turns out, I visited Ryūhō-ji one day in September 2005, and was lucky enough to get a photo of its treasure pagoda at just the right moment as the sun went down. If you're listening to the podcast version, check out the blogpost to see what I mean.
Ōtsuka ran the library there during the Kansei era-- a Japanese nengo (era) that ran from 1789 to 1801. This was a pivotal era for Sendai domain and for Japan in general, as this was the era where increasing attention was paid to the northern borders and increasing frequency of encounters with foreign, especially Russian, whaling vessels and warships. He thus had a role in educating the generation of Sendai retainers that took the clan into the 19th century and its crises of international incidents and the mad dash for adapting to the demands of a changing world and its attendant technological, linguistic, and national defense needs.
Ōtsuka died in 1801.
As I discovered on that day in 2005 when I visited the temple grounds, he was buried at Dōun-ji, where he once made astronomical observations-- which makes the grave in the meadow make a whole lot of sense. While the meadow still feels like it's in a world apart, light pollution means that while some stars come out over Sendai, the night sky isn't quite what he would have known. More's the pity.
But after everything, it's still there.
And to think I learned all of that because I literally stumbled on history.
- "Dōun-ji." Yaokami.jp https://yaokami.jp/1045188/
- Louise Watanabe Tung, "Library Development in Japan." The Library Quarterly: Information, Community, Policy , Apr., 1956, Vol. 26, No. 2 (Apr., 1956), 79-104, pp. 102-103.
- Miyagi Kenshi vol. 1 (1956), p. 166.
- Iwate Kenshi vol. 4 (1963), p. 1579.
- Kogure Tomokazu, The History of Modern Astronomy in Japan (Cham: Springer International Publishing, 2021), p. 3.
- "Satake Yoshine." Kotobank.jp. https://kotobank.jp/word/%E4%BD%90%E7%AB%B9%E7%BE%A9%E6%A0%B9-1078415
- "Observatory Dome (Treatise on the Kansei Calendar)" National Astronomical Observatory https://www.nao.ac.jp/en/gallery/weekly/2014/20140528-observatory.html
- "Tsuchimikado Shinto." Kokugakuin Encyclopedia of Shinto. http://eos.kokugakuin.ac.jp/modules/xwords/entry.php?entryID=366
- Hayashi Tsuruichi 林鶴一、仙臺, 一ノ関、盛岡及ビ弘前藩ノ和算家ニ就テ On the wasanists of the Sendai, Ichinoseki, Morioka, and Hirosaki hans. pp. 299-333 of The Tôhoku Mathematical Journal ser.1,v.16 1919, p. 302.
- "Etakuzan Ryūhōji." http://www.s-arakawa.jp/trip/tohoku/miyagi/sendai/ryuhoji.htm