Prospectus: Ninja Medicine – Mastering the Empirical Knowledge

            In the early modern period, the pursuit of medical knowledge was quickened by the advent of mechanical philosophy. The 16^th and 17^th centuries in Europe saw a paradigm shift from the Aristotelian geocentric view to the Galilean heliocentric view in astronomy, mathematization of nature and quantification of chemical science, and a quest for a universal cure in medical philosophy. While the Western countries were undergoing what we now call the scientific revolution, what was happening in the far East? Was the newly discovered understanding of nature in the West merely old news to the countries whose history is longer than that of the Europe’s? Or did they simply operate on a conceptual system that was so foreign to the West, and hence is the knowledge in the East not compatible with that of the West? The people in Asia too must have had science and medicine as these are necessary for sustaining human life. What was their medical philosophy? What was the science with which these countries operated? How much did they know? 

            These questions necessarily arise when one is working with the history and philosophy of science in the Western tradition. In fact, these are good questions to ask, even for someone like me who grew up in Japan. For come to think of it, throughout the mandatory school years until high school graduation, we rarely touch on subjects of science, medicine or theoretical philosophy in learning Japanese history before the 18^th century. The first time we really learn important writings in medicine or philosophy is when the Western influence frequented into Japan in the 19^th century. Even at a university level class in Japanese history, medicine or science is never a central focus of studies as they are said to be in studying the European history. Why is this? Why do we not hear anything about those subjects, which are so fundamentally important to human well being that it is inconceivable that Japanese people did not have them? The reason for this seems to be that Japan did not develop its own medical philosophy, but almost exclusively learned it from China. However, the wounds made by the Japanese swords and herbs that grew in Japan to make a cure or a poison must have been quite different from the mainland China’s. This suggests that Japan did in fact possess some sort of its own medical corpus that was more suited for its culture and environment, or else certain illness and wounds unique to people in Japan could not have been cured. Then, how is it that we never even learn anything about it?

The answer to this question appears to be mostly cultural, that is, people in Japan, unlike those in the West, did not publish their thoughts and theories for open criticism. Even if they left anything in documents, those were written by the members of the samurai class, who had little interest in how the ordinary people lived, and normally they concerned themselves with the political events and heroicizing their superiors. Some medical records of historically important people from those times still exist, but one cannot learn anything about generalized theories on cure or science. Do we, then, have no means whatsoever to find out what their understanding of nature looked like? Do we have nothing available to tell us what their medical practices looked like? Luckily, there were some who felt it important to leave the knowledge they acquired in document for later generations. They were the offspring of Ninjas in Sengoku, or the Warring States period (1467-1601; just before Edo period began in 1601). Ninjas were valued as professional spy organization, and often hired by the warring clans for the purpose of espionage and assassination. About one hundred years later, those descendants of Ninjas who feared the tradition was disappearing, left manuscripts containing everything Ninjas knew and had to learn. However, when the manuscripts were written in the 1680’s, much of Ninja knowledge had already been lost. What made it into the manuscripts were only the fractions of the knowledge kept in secrecy for a long time, and only the ones successfully passed onto the descendants after a few generations of almost complete inactivity.

What I discuss here is hence not a complete picture of what they knew. However, in this paper, I’d like to unveil the medical corpus of Ninja in relation to Chinese philosophy as much as I can, as it is largely if not entirely based on the wisdom of the continent, while at the same time, delving into what they did and did not understand about the medical philosophy passed on by Chinese manuscripts. I wish to shed some light on the inner workings of Medical Philosophy of Ninja in the 16th century Japan.