Many people in Japan think of cannabis as a foreign vice that wasn't introduced until the late 1960s when US servicemen on leave from military duty in Vietnam would bring it to Japan, or Japanese hippies returning from India or the Himalayas would introduce it to friends at home.
People who know that marijuana and hemp are the same plant may think that maybe in ancient Japan cannabis was important only as a fibre crop with low THC levels, the kind that gives smokers a headache instead of a "high". Is it true that (THC-rich) drug varieties and cannabis smoking are only a fairly recent introduction?
We admit that we don't know for sure if that is the case or not. We have researched the evidence and conclude that most likely, both non-psychoactive and psychoactive cannabis were available before 1948. That no laws were passed to prohibit or control cannabis then does not imply that none was used. Countries such as India and Morocco where cannabis was widely used only banned it because of American pressure, as did Japan. If legal availability did not lead to serious problems there was no reason for prohibition laws that would be difficult to enforce.
Cannabis has an important role in many religions, from Hinduism to Shinto. Several Shinto rites involving cannabis are entirely unrelated to hemp's use as a fibre plant and suggest an awareness of the psychoactive effects of marijuana smoke:
The roots of Shinto religion probably date back to the neolithic Jomon culture (10,000-300 BCE), and so it is quite possible that psychoactive cannabis had been available in Japan for well over 2000 years.
It is no secret that weedy (uncultivated) hemp in Hokkaido is still psychoactive. Indeed, every year some people try to harvest it in the autumn and get caught by the police. Its potency has been described as "quite good". It descended from cannabis legally grown by Japanese farmers until the late 1940s. Hokkaido hemp is by no means the only kind of indigenous psychoactive cannabis found in Japan:
"A survey of the THC, CBN and CBD content of hemp from all parts of Japan was reported by Dr. Keizo Watanabe. Marihuana from Tochigi and Hokkaido regions contained a 3.9 per cent and 3.4 per cent THC, respectively." (UNDCP 73/3)
These potency figures are comparable to marijuana available in Jamaica and Mexico in the 1970s.
Before worldwide laws against cannabis were introduced over the last few decades, there was no real incentive to breed plants specifically for low THC yield. There is no known genetic link between qualities desirable in fibre plants and low THC-yield. In fact, since the resin acts as a natural repellant against insects and other pests it is likely that more resinous plants are more robust. Thus plants could be usable both as industrial crops grown for fibre and seed and for medical and recreational purposes.
"Many of the older fibre hemp varieties were in actual fact rather rich in THC, since psychoactivity was not used as a selection/breeding criterion prior to the 1970s." (Prof. Szendrei, UNDCP 1999)
Many of the old hemp seed strains of pre-war Japan can no longer be legally cultivated because they don't meet the low THC-requirements imposed by some prefectural governments. This is even though the Cannabis Control Law does not specify any THC limits and regulates only based on the intended purpose of the crop. The Nagano prefectural government is refusing to issuing licenses to grow the traditional local mountain hemp and will only permit cultivation of a specially bred low-THC strain called "Tochigishiro". That strain was developed at Hiroshima University and its main cannabinoid is CBDA. Some old hemp farmers complain that it produces fibre of inferior quality when compared to more traditional strains that do contain noticable amounts of THC.
Because potent cannabis is uncommon at northern lattitudes it seems likely that Hokkaido hemp is unrelated to Siberian hemp and was introduced from further south. It may have originated from seed hemp cultivated there for making oil, bird feed or human food. In other countries varieties grown for seed production were sometimes psychoactive. For example, the most common type of bird seed hemp in the USA before cannabis was prohibited was a strain known as "Smyrna hemp". Besides seeds this plant from modern day Izmir, Turkey also produced resin for hashish known as "Smyrna powder".
Another possibility is that potent cannabis was introduced from India or Southeast Asia, where cannabis smoking has a long history. Until 1948 cannabis could be legally imported into Japan from other countries. Marijuana, hashish or viable seeds could be shipped from India and Thailand to Japan. Japan has a long history of trading with China, which in turn sent ships as far as Africa. In the 8th century Buddhism reached Japan from India via Nepal and China. Later Japan was trading with Portugal which had a base in Goa, India and with the Dutch who colonized Indonesia, places where marijuana use was not uncommon. The famous Silk Road carried trade from Arabia, Persia, Afghanistan all the way to Japan.
It is interesting that Kiseru pipes ("ksher" in the Khmer language) which until the 20th century were also popular for smoking tobacco originate from Cambodia, were cannabis is still sold from street stalls today. It would not be surprising if the smoking materials travelled along the same route as the smoking instruments. The bowls of kiseru pipes are much smaller than for western tobacco pipes, which is consistent with the fact that a psychoactive dose of cannabis is from 1/2 to 1/10 the weight of a tobacco cigarette.
The predominant cannabinoid in marijuana plants is THC. In fibre hemp on the other hand the most common cannabinoid is CBD, which is not psychoactive. In 1956 a study for the Japanese government analyzed domestic cannabis plants. It found THC but no CBD... The study concluded that the tested plants were closer to South-East Asian drug hemp than to northern fibre hemp:
"From the spectrophotometric studies of our domestic hemp, it is concluded that it contains tetrahydrocannabinol [THC], or an analogous compound; and in general the hemp plants grown in Japan give a resin more similar to the Malayan [Malaysian] resin reported by Biggs than to the Canadian resin." (Asahina 1957)
We don't know much about the lives of peasants in medieval Japan, since history as we know it is essentially the version of events reported by the literate samurai class, who considered the common people not much different from their farm animals. What we do know is that hemp was smoked in rural areas at least as recently as the 1940s. We don't know if this is because of the tobacco shortage during the war or if it reflects a more ancient heritage. The Shinto aspects and the reported THC levels of Japanese cannabis strains suggest the latter.
Until cannabis cultivation was largely halted, cannabis flowers were always cheaper than alcohol brewed from valuable rice, since they were a byproduct of growing the plant for seeds and fibres. Rice on the other hand was a precious commodity which was used to pay taxes and feed armies. In fact, during the Edo era rice was grown largely for the samurai class while the rural population had to survive on other crops. The Tokugawa gained dominance because of the large amounts of rice grown in the Kanto plain. This was food for samurai, not for peasant farmers. Therefore it seems likely that expensive sake was the drug of choice of samurai while peasants might have used cheaper hemp to relax.
Japanese medicine is based on both traditional Chinese herbal medicine and Western (mostly German) medicine. Both Chinese and western medicine used cannabis for healing. Cannabis was in use as a herbal medicine in China for some 5000 years. Psychoactive strains exist particularly in Southern China, near Vietnam and Thailand. The central Asian part of China bordering on Turkmenistan was a hashish exporting region until the 20th century. In Western countries cannabis came into medicinal use from the 1830s. Cannabis extracts were sold in pharmacies until the 1940s or 1950s. Countries like Britain and Germany imported seeds of psychoactive cannabis strains from India or Africa to grow medicinal plants. Such medicinal plants were also cultivated in Japan. Indeed they are still being cultivated at the Tokyo Metropolitain Medicinal Plant Garden:
Torao Shimizu examines the gray sky and gives the brown earth a little kick. "This is good climate for marijuana," he says. "It grows easily here." On the other side of a high double fence, safeguarded by motion detectors, a row of tall green pot plants sway gently in the morning breeze. (Japan Times)
If potent cannabis was not available long before rice and had not arrived with Chinese medicine 1300 years ago either, it probably would have been introduced with western medicine 130 years ago. Today Cannabis is no stranger in Japan and it probably never was one. It is only by knowing the facts that we can learn to deal with it in the least harmful way.