Knowledge of nature and craftJapanese technology, engineering, and agriculture. As a result, incorporating these fields into our
history of science in Japan becomes more feasible, although then the historian must also possess
the technical knowledge to interpret these results. While the influence of Chinese technologies at
moments of greater openness—the early ritsuryō period and the late medieval era—remains part
of the histories of iron- working or carpentry, internal developments driven by social change in
Japan at other times must also be factored into the equation.^29
Furthermore, the history of astronomy in Heian and Kamakura Japan, problematizes the
depiction of Japan from 894 to 1401 as secluded (even “semi- secluded”) enough to have prevented
Chinese texts or developments from getting there. Certainly a depiction of early medieval Japan
as “semi- secluded” goes against the grain of current scholarship: while it is possible to portray the
late classical and early medieval period connection to the continent as minor in terms of the
quantity of objects and persons coming across, or in terms of a lack of newly composed Chinese
literature documented in Japanese aristocratic libraries, unofficial links to the continent inargua-
bly continued to have significant effects on Japanese practices.^30 Twelfth- century debates on the
winter solstice, for example, included discussion of new techniques for astrology, and newly
imported equations for mathematical astronomy were employed for predicting a solar eclipse in
1228.^31
Nevertheless, during the period from 862 to 1684 the Japanese court failed to officially adopt
a new astronomical system for calculating the calendar, a fact that historians have tended to inter-
pret as a sign of stagnation or a lack of interest in science. Like many scholars before them, Sugi-
moto and Swain appear to have assumed that developments in science or technology in China
uniformly represented improvements or progress, and that this must have been obvious to
observers and actors at the time—meaning that if new developments were not embraced by the
Japanese, some force had to have been hindering adoption. For Sugimoto and Swain, the logical
culprit was the cessation of official missions to China.^32
These are positivist assumptions, and are not necessarily borne out by the historical record,
however.^33 The court was active during the late Heian and Kamakura periods in hearing objec-
tions to and tests of official mathematical astronomy. They simply chose not to adopt the Chinese
innovations.^34
On the other hand, what Sugimoto and Swain’s work correctly emphasizes is the way in
which the history of Japanese science and technology is deeply entwined with and indebted to
the history of science and technology in China and Korea. While a historian looking for “Jap-
anese science” might want to focus on innovations and developments unique to the archipelago,
in many ways Japanese intellectuals and technicians were working in a larger sphere that was
once called Chinese Science, but which is now, in recognition of its larger geographical context,
called East Asian Science, Technology, and Medicine.^35 The transfer of Chinese, Korean, and
Indian (and perhaps Islamic) concepts and technologies to Japan is perhaps the major topic for the
history of Japanese science and technology before 1600, although this transfer should not be
assumed to have been automatic, nor necessarily successful.
Toward a new history of science in premodern Japan
Creating a new survey of the histories of science and technology in Japan that includes the pre-
modern period is a daunting task, but one that will hopefully bear fruit in coming years. Since the
1970s, a number of specialized works on the history of science and technology in Japan have
appeared. In mathematics and astronomical journals, scientists have continued to reconstruct old
methods and evaluate them against the new. Broader definitions of “technology” and “science”—
definitions that cover all varieties of knowledge associated with the natural and material world,