Cannabis has been cultivated in Japan since the Jōmon period of Japanese prehistory approximately six to ten thousand years ago.

Hemp remained ubiquitous for its fabric and as a foodstuff for much of Japanese history, before cotton emerged as the country's primary fiber crop amid industrialization during the Meiji period.

The proportion of the Japanese population that has used cannabis at least once was 1.8 percent in 2019, making it the second most popular illicit drug in the country behind methamphetamine.

[3] Cannabis was likely introduced roughly 18,000 years ago via a land bridge that connected the Asian continent to the Japanese archipelago.

[1][6] Owing to the plant's association with purity,[a] cannabis hemp fibers were also used by Shinto priests for ritual cleansing and to exorcise evil spirits, a practice that continues to the present day.

[6] The ascendance of the feudal daimyo led to the further cultivation of commodity crops like hemp, which provided them an additional source of revenue through both sale and taxation.

[6] As Japan pursued a policy of economic isolationism during the Edo period, agricultural plots in the south of the country were used to grow cotton, which was highly valued at the time, while hemp was grown on a smaller and more irregular scale in the north.

Historians have speculated that the wide availability of cannabis may have made it the intoxicant of choice for commoners, contrasting the monopolization of sake extracted from rice by the upper classes.

[1][8] As a result of higher agricultural yields prompted by industrialization during the Meiji period, cotton came to gradually replace hemp as Japan's primary fiber crop.

[12] Contemporaneously, specialized fine hemp clothing produced using modern weaving techniques began to emerge, though the high labor costs associated with creating these garments meant they were purchased and worn exclusively by the wealthy.

[13] By the early 20th century, cannabis-based cures for insomnia and muscle pain could be purchased in Japanese drug stores.

[1][8] Its ritual use also continued, with early 20th century American historian George Foot Moore observing that Japanese travelers would present cannabis leaves as offerings at roadside shrines to ensure safe trips.

[13] While the ostensible purpose of the law was to protect Japanese society from narcotics, historians have speculated that American petrochemical interests may have sought to restrict the hemp fiber industry in order to open Japan to foreign-made polyester and nylon, noting that the sale of amphetamines was permitted until 1951.

[8] Originally passed in July 1948,[14] the law has subsequently been modified multiple times, with each revision adding stricter penalties for violations.

In 1980, English musician Paul McCartney was detained in a Japanese prison for nine days after cannabis was found in his luggage at Tokyo's Narita International Airport.

[14][35] Japanese hemp cultivators are required to grow Tochigishiro, a low THC strain with little euphoric potency that was developed after World War II and which is distributed to farmers as seeds by the government.

[13] Less than one hundred total licenses are granted to Shinto shrines, which grow and process small amounts of cannabis for ritual use.

[42] CBD is legal in Japan and been sold in the country since 2013,[21] with CBD-infused products such as oils, cosmetics, and foodstuffs being readily available at both specialty shops and major retailers.

[21] The Cannabis Control Law was upheld by the Supreme Court of Japan in a 1985 challenge, while the Japanese Drug Abuse Prevention Center (an organization under the supervision of the Ministry of Health and the National Police Agency) maintains a policy that cannabis is harmful to the immune and respiratory systems, and can induce manic-depression.

[14] A 2012 projection by author and businessman Funai Yukio [ja] estimated that legalizing recreational cannabis in Japan could generate up to ¥30 trillion (US$273 billion) in revenue.

[47] In 2021, the Ministry of Health convened a panel of experts to make recommendations on potential revisions to the Cannabis Control Law.