[Small Leonid Watch]

Tani Jinzan and A Leonid Conflagration;
A Two-Fold Tragedy of Observation and "Theory" in Edo Era Japan

Steven Renshaw and Saori Ihara

A version of this article also appeared in the Griffith Observer
Volume 62, Number 11; November, 1998.

Following the earth's passage through the tail of parent Comet Tempel-Tuttle, 1998 holds high expectations for brilliant displays of Leonid Meteors. Leonids may have been observed as early as the 10th century A.D., and though somewhat unpredictable, have provided views of "meteor storms" to people of many cultures (Roggemans, 1989). There have been several reports of this periodic stream causing great awe and fear. However, a dazzling display of Leonids seen in the rather remote Japanese city of Tosa (now Kochi, Japan) in the late 17th century confirmed for many citizens, and one rather brilliant but somewhat luckless calendar scholar in particular, the idea that events in heaven are inextricably related to events on earth.

In the early stages of the Edo era (1603-1867) [1], Confucian pragmatism and the fact that the Japanese lunar calendar was some two days in error had begun to persuade Tokugawa Shogunates to value mathematical aspects of astronomy somewhat more than celestial divination in the development of a calendar [2]. However, lasting much longer than in Europe, Japanese "astronomy" continued to be a rough mix of empirical observation and astrology for some time. A good example of this mix is found in the work of Tosa calendar scholar Tani Jinzan.

Tani (1663-1717) later became a symbol of national pride in the post Meiji Era for what was seen as his renaissance attitude and independent thought. He is also well remembered for his work with Shibukawa Harumi in which he used precise observation to further confirm adoption of a new lunar calendar in 1684. However, as a child of Confucian classics and archaic Chinese astrology, he also continued to play with a "system" which was often termed the "Theory of Areas" (Okamura, 1988). While based on Chinese mathematics, this was not a Keplerian concept or theory in any modern definition of science, but rather the proposition that areas on earth correspond to areas in the sky. Somewhat similar to Western astrology, domains on earth had complementary "areas" in the heavens. Events such as wars, conflagrations, and territorial change that occurred in "earthly" domains were associated with complementary events in the sky, and vice versa. Sometimes earthly events were indeed "real" and associated with some unusual event such as a comet or eclipse. At other times, imagination or political expediency could produce all the "evidence" needed for confirmation of associations [3]. We need only remember the tragic events that occurred with the appearance of Comet Hale-Bopp to realize that "imaginary" associations with astronomical phenomena are neither historically nor culturally bound.

Following the "Theory of Areas", the Edo era found most prefectures in Japan with "sister" constellations or asterisms in the sky. The constellation which includes the stars called "Neko no Me" (cat's eyes) in Japan (Castor and Pollux in the West) marked the celestial domain corresponding to the earthly domain of Tosa. In Chinese based star charts, this constellation was also called Ishuku, meaning "well" (probably because of its similarity to the Chinese Kanji for a water "well" which looks a bit like the pound sign on a telephone).

[Ishuku Water Well]

With some imagination, the Chinese Character (Kanji) for "water well" (Ishuku) may be seen in the stars of the constellation of Gemini. (Steven Renshaw and Saori Ihara with The Sky IV; Software Bisque)

Ishuku is the 22nd sei shuku or 1st "moon station" of the Red Bird of Summer (see Watanabe, 1984). Though it is difficult to discern exactly when and why Tosa was assigned the two bright stars of Gemini along with their sei shuku, it is probable that these stars were chosen because of their celestial proximity (declination) to Tosa's corresponding geographic latitude. Kochi (old Tosa) is located E 133 degrees, N 33 degrees. Allowing for precession, the stars of Castor and Pollux were located even closer to the celestial "latitude" of 33 degrees in ancient times than they are today. Obviously, under such circumstances, the "cat's eyes" would transit at the zenith. Thus, celestial latitude and "placement" along the ecliptic were probably combined with Tosa's geographical latitude to form the sibling relation in an era preceding that of the Tokugawa Shoguns (Yamamoto, 1994; Okamura, 1995).

Tani rarely looked for imaginary associations but maintained an empirical skepticism with regard to most "theory", this despite his relative isolation from the world outside of Japan and any training in scientific method. Ironically, however, he found what he considered strong "evidence" for the "Theory of Areas" in a tragedy that occurred in the year 1698 in Tosa. Here, there was an event on earth and a phenomenon in the sky that indeed appeared conjointly. While fires were all too common in the Edo era, a particularly bad conflagration took place in Tosa that year. At 12:30 on the afternoon of November 8, flames began to leap from a small home in a northern suburb. From his home atop a hill north of Tosa, Tani Jinzan observed and later recorded the events of the day and evening: [4]

The fire came close to the castle, burnt twelve governmental buildings and 170 Samurai houses. It then moved to the East of the Castle and burned about 2000 houses in the downtown area. Many were killed and injured. The fire finally ceased around the time of the wild boar [10:00 P.M.].

On the same night, Dai Ryuusei [great meteors] flew into Ishuku [the "well" which included the constellation of Gemini] and were streaming down several shaku [1 shaku is about 1.2 degrees]. They disappeared after awhile. Ryuusei flew as if they were weaving a cloth tonight, and many people observed this.

[Tosa Leonid Watch]

Tosa's citizens watch the Leonids while standing within their burned city. A rendering of Tosa Castle (present day Kochi Castle) may be seen to the side. (Drawing by Saori Ihara and Steven Renshaw)

The meteor shower was, of course, the Leonids. 1698 was a year quite close to their 33.3 year cycle (See again Roggemans, 1989). To the residents of Tosa, these meteors were the heavenly manifestation of the conflagration they had experienced on earth. Meteors "flew" into Gemini as the fire had "flown" through Tosa. While seen as something negative of course, this Leonid shower was not viewed as the wrath of some god but rather as a "heavenly" complement to events on earth. Most local residents, within the prevailing astrological view, felt that all was not well with Tosa, and the heavens were mirroring their plight.

[Leonid Sim 1]

Simulation of Tosa's Eastern Sky (including Zenith) at midnight (12:00 AM November 9, 1682) about two hours after the fire had "ceased". Tosa is located E 133 N 33 degrees. The Grid is based on altitude/azimuth coordinates. (The Sky IV; Software Bisque)

Simulating the night sky on this date at midnight local time, two hours after the fires had "ceased", the bright stars of Gemini had risen about about 3 hours earlier; the shower's radiant, Leo, was coming up from the Eastern horizon. However, as the night progressed, and Gemini rose higher and higher toward the zenith, meteors were no doubt seen to be moving from the East toward the top of the sky and thus into the constellation of Gemini, the heavenly "sister" of Tosa.

[Leonid Sim 2]

Simulation of Tosa's Eastern Sky (including Zenith) at 4:00 AM on November 9, 1682. Ishuku (Gemini) may be seen in transit as the Leonid radiant is now clearly visible. The Grid is based on altitude/azimuth coordinates. (The Sky IV; Software Bisque)

The association of the fire, meteors, and Tosa's celestial domain gave Tani "evidence" to confirm in his mind the "Theory of Areas". As the remainder of his collected works indicates, he continued to hold this theory as a primary "axiom" for the rest of his life. In a way, the conflagration produced both a tragedy in loss of human life and a tragedy in scientific development.

Tani's experience with the Leonids in many ways represents the "two steps forward, one step backward" development of astronomy in Japan which seems to have troubled thinkers in this country for many years prior to the Meiji Reformation [5]. Plagued by various ailments throughout his life, he lived in virtual poverty, his family having lost the wars that ushered in the Edo era. Even so, he gained the acclaim of fellow "calendar scholars" such as Shibukawa Harumi who with help from Tani's observations, was primarily responsible for reforming a calendar that had not seen change in some 800 years. There can be little doubt that Tani did indeed have a sense of the importance of evidence and precise observation. However, despite this sense of empiricism and a grounded base in Chinese mathematics, he like so many other Japanese scholars of the time, was unable to avoid fitting his "theory" to the facts rather than allowing the facts to lead to more well defined propositions.

There are indications that Tani knew the tragedy of his limitations. Deprived of information from the West, he often expressed that his greatest frustration was his inability to juxtapose his observations and calculations with the then held view of the "heavens". Tragedy also followed Tani in other ways. He spent the last twelve years of his life under "house" arrest. There is no record of the exact nature of his "crime". Though he tried to continue observing and developing more congruent systems of fact and "theory", he was never really able to break away from the mysticism and political barriers of his time and place. Broken, he died of a fit of apoplexy in 1717 (Okamura, 1988).

[Tani Tomb]

Tani's tomb, located on the top of a small mountain in Tosa Yamada just east of modern Kochi City (old Tosa). The simple rock memorial has been covered by flags and prayers of generations of students seeking Tani's guidance for their college entrance exams. (Photo by Steven Renshaw and Saori Ihara)

Interestingly, his tomb is located at the top of a long series of old rock steps leading due north up a small mountain in Tosa Yamada (just east of Kochi City). The tomb is quite simple; Tani specifically requested it be so since he felt that "elaborate tombs bring rubbish on ones family". However, his status as a national historic figure in Japan has made this simple tomb a shrine, such status bringing all the flags, written prayers, and wishes of generations of young high school students who have hoped that the august scholar's zest for learning will guide them in their college entrance exams.

History of Science seems to be replete with combinations of observation and faulty logic, worthwhile contribution and mystic lore. In thinking of a European scholar like Kepler who had his own "Theory of Areas", long term implications of his contributions to science may dwarf the actual accomplishments of Tani Jinzan. Yet, in his own way, Tani paved the way for opening Japan to new ideas and inevitable scientific revolution by placing importance on observation and evidence as a base for knowledge claims. In many ways, Tani can be faulted no more for his astrological associations than Kepler who had his own bit of mysticism. Yet there are other similarities in these men, separated by time and half a globe. Both had attitudes which later inspired scientific thought in future generations of scholars. When viewed in this context, both were perhaps prisoners of their historical circumstances.

While we look forward to brilliant displays of the Leonids this year, we also hope that no great conflagration, either natural or devised by ignorance and mysticism, will occur conjointly. These nights, the "cat's eyes" still peak at us through the winter months, though they transit a bit further south of the zenith here in Kochi (Tosa) than they used to. When we see them, we cannot help but think of the old "calendar scholar". With somewhat touching irony, Tani's advice, which has inspired generations of Japanese students, may transcend both time and culture:

As long as you have a will to go your way... above all, if you have a big heart and strong mind and are willing to read the great books and make them your wings, it will be the best study of all. (Jinzan Shu, Tani T., 1910)


Hirose, H. (1972) Nihonjin no Tenmonkan (The Japanese Astronomical View). NHK Books, Tokyo.

Nakayama, S. (1969) A History of Japanese Astronomy; Chinese Background and Western Impact. Harvard University Press, Cambridge, Mass.

Okamura, K. (1995) Tosa Tenmon Sanpo (Tosa Astronomical Promenade). Kochi Shinbun Co. Ltd., Kochi, Japan.

Okamura, K. (1988) Tosa no Rekigakusha (Calendar Scholars of Tosa). Tosa Shupansha, Kochi, Japan.

Roggemans, P. (Ed.) (1989) Handbook for Visual Meteor Observations. Sky Publishing Co., Cambridge, Mass.

Sugimoto, M. and D.L. Swain (1989) Science and Culture in Traditional Japan. Charles E. Tuttle and Co., Tokyo.

Tani, T. (1910) Jinzan Shu (Works of Jinzan). Compilation of Writings of Tani Jinzan (Originally compiled by Tani's son, Tani Kakimori, and published by descendant Tani Tateki). Noritatsu Sawamura, Seishoudou, Tokyo.

Uchida, Masao (1990) Koyomi to Tenmon: Ima Mukashi (Calendars and Astronomy: Now and Then). Maruzen Co. Ltd., Tokyo.

Watanabe, T. (1984) Kinsei Nihon Tenmon Gakushi; Vol II (A View of Japanese History of Astronomy in Modern Times; Vol II). Koseisha Kosaikaku, Tokyo.

Yamamoto, T. (1994) Kochi Ken no Rekishi (History of Kochi Prefecture). Yamakawa Pub. Co., Tokyo.

For those who would like to get more information about the Leonids from the web, the following links may be useful:

Nasa's Web Page on Leonids

Gary Kronk's Web Page


1 "Edo" is the old name for Tokyo which was the center of rule for Shoguns of this era. "Tokugawa" (from the original Tokugawa Ieyasu) refers to the family line of all shoguns of the Edo Era.

2 Hirose (1972), Uchida (1990), and Watanabe, (1994) have exhaustive discussions of the manner in which astronomy for purely divination purposes began to be replaced by "Western" concepts and more scientific methodologies in the latter part of the Edo era. An English discussion may be found in Nakayama (1969) and Sugimoto and Swain (1989).

3 We refer to the "cosmology" under discussion as a "Theory of Areas". More detailed description in English of the ways in which Japanese adopted and used the classic Chinese astrological works of the "T'ien-kuan shu" and "T'ien-wen shu", on which this "theory" was based, may be found in Nakayama's (1969) classic work on the History of Japanese Astronomy; Chinese Background and Western Impact.

4 Tani's observations of the fire, the subsequent swarm of Leonids, and reactions of townspeople were recorded in Jinzan Shu (Works of Jinzan, compiled and published by his descendant, Tani Tateki, in 1910). In our translation of this work, we have also relied on Okamura (1988) and Yamamoto (1994) for help in interpretation of the Classical Chinese style of writing used by Tani Jinzan.

5 Readers should again refer to Nakayama (1969) for a detailed discussion of the difficulties Shibukawa and colleagues such as Tani Jinzan had in trying to bring calendar reform to a land symbolically ruled by an emperor whose main concern on any given day may have been to know in which direction not to walk and a disinterested Shogunate who had real power in the country but was forced only by economic and political necessity to adopt some change.

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Steven L. Renshaw

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