Traditional Chinese medicine dates back to the Shang Dynasty, or about 3000 years ago. Some of the ancient hieroglyphic characters found on bones and carapaces from the Shang Period include health-related descriptions such as illness and disease. While shamanism was dominant during this period, it is likely that empirical medicine was also practiced. During the Han Dynasty, the "three principal classics of Chinese medicine and Kampo medicine" were compiled and established, namely, the Shinno-honzokyo, Koteidaikei, and Shokan-zatsubyoron
Shinno-honzokyo is the oldest extant medical textbook in China, and describes 365 different varieties of raw materials for crude drug, a number equivalent to each calendar day in a year. It was compiled between the 1st and 2nd centuries and while the editor remains unknown, Shinno, the father of medicine and agriculture, is honored as the legendary originator. In the text, crude drugs are categorized into three classes, Jo (superior), Chu (middle), and Ge (inferior), according to their therapeutic effects. The interactions between the different botanicals are also explained.
Kotei-daikei is a compilation of organized and edited medical theses written after the Chunqiu Warring States period, and was completed between the end of the Former Han Period and the beginning of the Later Han Period. Named after Kotei, another illustrious emperor as renowned as Shinno, Koteidaikei consists of two distinct sections, Somon and Reisu, and the content is divided into basic science such as physiology and pathology, and clinical medicine such as acupuncture, moxibustion, and other clinical practices.
Shokan-zatsubyoron is a collection of prescriptions by Zhang Zhong Jing in the Later Han Dynasty (early 200 A.D.). Originally a single text, it was later divided into two separate texts, Shokanron and Kinki-yoryaku, as they are known today. Shokanron focuses on cold-induced or acute febrile diseases, while Kinki-yoryaku focuses on chronic degenerative diseases.
Traditional Chinese medicine was actively incorporated and imitated in Japan during between 250 A.D. to 538 A.D. (Kofun Period) and 793 A.D.
In the 5th and 6th centuries, traditional Chinese medicine was imported to Japan via the Korean Peninsula, along with Buddhism and other cultures. By the 7th century, diplomatic delegations such as Kenzuishi and Kentoshi were sent to China as needed, and helped introduce the healthcare system and medicine directly from China.
Other important medical texts compiled over the course of multiple periods include Shohinho in the Six Dynasties of Ancient China, Shobyo-genkoron in the Sui Dynasty, and Senkinho and Gedai-hiyoho in the Tang Dynasty.
The enactment of the Taiho Code in 701 A.D. created Japan’s first medical affairs system, Ishitsuryo, and established Tenyaku-ryo, the ancestor of today’s Ministry of Health, Labour and Welfare, Department of Medicine, and Department of Pharmacy. The healthcare system created during this period was based on Shohinho, Somon, Honzokyo-shicchu, and other textbooks.
The Shosoin in Nara prefecture houses 40 raw material for crude drug specimens that were dedicated to the Todai Temple in 756 A.D. As herbal specimens collected before 1250, these raw materials for crude drug have unprecedented value. Daio (Rhubarb) and ninjin (Ginseng), which are still used in today’s prescriptions, are examples of the herbal specimens. Interestingly, an extensive scientific study conducted between 1948 and 1951 showed that these antiquated botanicals still retained their therapeutic potency.
Japanese medicine in the 10th century (Heian period) was still merely an imitation of traditional Chinese medicine. This was when Japanese physicians began to take initiative and compile their own pharmacopoeias.
Compiled in 984 A.D. by Yasuyori Tanba, Ishinpo is Japan’s oldest extant medical book with 30 volumes of citations from numerous Chinese medical texts. Ishinpo is the definitive text, tracing the roots of Japanese medicine to Chinese medicine. The printing techniques of the Sung Dynasty enabled the compilation and reprints of new medical books and important classics. These included Taihei-keimin-wazai-kyokuho, which contains some of the formulations that are still in use today, such as juzentaihoto and anchusan. Other texts included Shokanron and Kinki-yoryaku. Keisi-shorui-taikan-honzo contains monographs on 1744 medicinal substances, five times the number of monographs in Shinno-honzokyo, and it remains the authoritative text on materia medica.
By the late 12th century (Kamakura period), the Japan-Sung trade had stimulated commercial relations between Japan and China, and led to an influx of Sung dynasty medical texts. At the same time, Japanese physicians began to adopt their own medical theories, as exemplified by the sentiment of Ton-isho written by the priest and physician, Shozen Kajiwara. As priests replaced court physicians as providers of healthcare, the scope of people receiving healthcare extended to the general public.
The Jin-Yuan period in China marked the emergence of four men who revolutionized the medical theories of their time: Liu He Jian, Zhang Zihe, Li Dong Yuan, and Zhu Dan Xi. Prescriptions such as Bofutsushosan and Hochuekkito were created by Lin He Jian and Li Dong Yuan during this period.
The Japanization of traditional Chinese medicine took place between the 14th century (Muromachi period) and the early 17th century (early Edo period). This began with Sanki Tashiro’s return to Japan with what was then considered the most advanced school of medicine, namely Jin-Yuan medicine, and in particular, Li-Zhu medicine. His disciple, Dosan Manase, encouraged the spread of this medicine and laid the foundations for the Goseihoha School (School of Later Developments in Medicine), which flourished during the early Edo period. The medical practices carried out by Dosan’s successors, Gensaku Manase, Gyuzan Katsuki, Genya Okamoto, and other leaders of the Jin-Yuan school were referred to as the Goseihoha School.
With advances in Jin-Yuan medicine in China, Honzo-komoku, the authoritative text on materia medica, and medical encyclopedias such as Manbyo-kaishun, the bestseller during the Edo period and the source of prescriptions like Rikkunshito, were compiled.
Hideyoshi Toyotomi’s invasions of Korea led to the import of typography techniques, which further facilitated the diffusion and Japanization of Chinese medicine.
The Kohoha School (School of Classical Formulas), the dominant school today that emerged in the late 17th century (mid Edo period), was pivotal in accelerating the Japanization of Chinese medicine. By eliminating speculative theories such as Inyo-Gogyo of the Goseihoha School, the Kohoha School advocated a return to the practical theories of Chinese medicine such as those found in Shokanron and Kinki-yoryaku. Proponents of this movement included Gen-i Nagoya, Konzan Goto, and Ekiken Kaibara, the latter well known for his work in Yojokun.
In 1759, Toyo Yamawaki of the Kohoha School wrote the first anatomical text, called Zo-shi. Subsequently, Todo Yoshimasu, who earned renown with his recognition by Yamawaki, proclaimed that "all diseases derive from a single toxin", and used strong drugs to treat the toxin, which meant the disease.
Todo wrote the Yakucho, a text that expressed the Kohoha School’s original theories on the therapeutic effects of medicinal plants in Shokanron and Kinki-yoryaku. He also recompiled Shokanron by prescription and published the clinically useful Ruijuho, a bestseller in its day. Todo’s oldest son Nangai modified his father’s theories and became the first physician to advocate the theory of Kiketsusui (vital energy, blood, and body fluids). Bunrei Inaba wrote the Fukusho-kiran, which helped establish the Japanese method of abdominal diagnosis.
In the 18th century (late Edo period), practitioners that integrated the perceived strengths of the Goseihoha and Kohoha schools emerged, as did those who emphasized the clinical applications of Kampo preparations, and were dubbed the Secchuha (Eclectic School). Tokaku Wada and Sohaku Asada were representative figures in this school. In 1804, Seishu Hanaoka succeeded in combining Dutch medicine (Rangaku) with Kampo and became the first surgeon to treat breast cancer with surgery and Tsusensan, a Kampo formulation. One of his students, Soken Honma, wrote the Naikahiroku and Yokahiroku in an effort to integrate Kampo with Western medicine, and his school later became known as the Rankan Secchuha.
Sohaku Asada, a giant in Kampo medicine, who was practicing during the late 19th century (between the end of the Tokugawa Shogunate and the early Meiji period), was appointed as the official doctor for the Edo Shogunate after successfully treating cholera and measles. After the Meiji Restoration, Asada became the imperial physician and contributed greatly to the perpetuation of Kampo medicine. Futsugo-yakushitsu-hokan and Futsugo-yakushitsu-hokan-kuketsu were Sohaku Asada’s most cherished formularies and source texts for prescriptions used in modern Japanese Kampo.
The tide of medical modernization that swept Japan during the late 19th century (Meiji period) led to the rapid decline of Kampo.
With the aim of facilitating modernization and increasing wealth and military power, a new education and healthcare system favoring Western medicine was established by the Meiji government in 1874. The new system institutionalized the examination system, which based its structure on seven Western medical subjects, as well as the licensure of medical practice. Further, under the Dajokan (Grand Council of the State) proclamation in 1883, the medical license system granted licenses only to physicians who had passed the national exam to practice medicine. By 1895, the 8th National Assembly of the Diet vetoed a request to continue the practice of Kampo, driving it to the brink of extinction. Yet despite losing it legal standing, the tradition was kept alive primarily at the grass-roots level by dedicated physicians, pharmacists, and vendors of traditional medicines. In addition, Keijyuro Wada’s self-published Ikai-no-tettsui in 1910, which criticized Western medicine and commended Kampo medicine, sparked a revival.
In 1927, Kyushin Yumoto published the historic Kokan Igaku, which triggered the revival of Kampo in the early 20th century (Showa period). Subsequently, Yumoto earned the title as "the father of the revival of Kampo" and "the pioneer in the integration of Eastern and Western medicine."
Also during this period, the writings of Keijyuro Wada and Kyushin Yumoto laid the foundations for a gradual renaissance of Kampo medicine. The efforts of Yoshinori Otsuka, Domei Yakazu, Shiro Hosono, Kenzo Okuda, and other leaders of the pre- and postwar Kampo revival movement led to the establishment of the Japan Society for Oriental Medicine (JSOM) in 1950.
During the 1960s, a series of adverse drug reactions raised concerns about the exclusive dependence on modern drugs for treatments.
In 1960, raw materials for crude drug listed in the Japanese Pharmacopoeia received official drug prices under the National Health Insurance (NHI). In 1975, "The Handbook of OTC Kampo formulations" was published under the supervision of the Pharmaceutical Affairs Bureau of the Ministry of Health and Welfare. Thus, the Showa period was a time of gathering momentum for the revival of contemporary Kampo.
In 1976, 33 Kampo formulations for prescriptions were added to the National Health Insurance drug price list, and new formulations have continued to be added since then. Currently, 148 Kampo formulations are on the drug price list.
Prompted by the Pharmaceutical Affairs Bureau’s 1985 notification on the handling of Kampo extract formulations for prescription, a new set of quality standards for Kampo formulations was established to ensure the equivalence between Kampo extract formulations for prescription and standard decoctions.
In 1991, the Japan Society for Oriental Medicine (JSOM) was officially registered as the 87th member of the Sectional Committee of the Japanese Association of Medical Sciences.
In 2001, a new section for education in Oriental medicine to foster the "basic understanding of Kampo medicines" was added to the Model Core Curriculum of medical schools. In 2002, the Model Core Curriculum of pharmaceutical colleges also included a section on education in "Raw Materials for Crude Drug and Kampo formulations in modern healthcare". Today, numerous textbooks have been published and all medical and pharmaceutical colleges and universities have incorporated Kampo medicine into their curricula.
In 2006, the Japanese Board of Medical Specialties designated the Japan Society of Oriental Medicine (JSOM) member physicians as Kampo specialists, and many universities and public research centers subsequently established research departments and outpatient clinics specializing in Kampo medicine. The number of scientific presentations on basic and clinical research of Kampo medicine at academic societies has also increased rapidly. These changes herald a new era for the adoption and development of Kampo medicine.