The global cannabis regulatory landscape is a patchwork of rapidly evolving laws and societal attitudes, presenting a complex challenge for international businesses. While some jurisdictions have moved towards medical use or even adult recreational legalization, Japan has historically maintained one of the world's strictest stances against cannabis. However, significant legal reforms enacted in late 2023, largely coming into effect through 2024 and 2025, have both clarified and modified Japan's approach. For international businesses, particularly those in the wellness, pharmaceutical, or consumer goods sectors, understanding these changes is crucial to navigate the Japanese market compliantly and avoid potentially severe legal and reputational consequences.

This article delves into Japan's traditional position on cannabis, unpacks the landmark legislative changes of December 2023, clarifies the current legal status of cannabis and related substances—including THC, CBD, and newly controlled synthetic cannabinoids—and explores the practical implications for companies operating in or engaging with Japan.

Japan's Historical Zero-Tolerance Approach to Cannabis

For decades, Japan's approach to cannabis has been characterized by strict prohibition and minimal tolerance, a stark contrast to trends seen in some Western countries.

Early Regulations and the "No Use Offense" Anomaly

Interestingly, Japan's first dedicated cannabis legislation, the Cannabis Control Act (Taima Torishimari Hō), enacted in 1948, was primarily designed to regulate the cultivation of hemp for industrial fiber, a significant industry at the time. Psychoactive use of cannabis was not widespread or a major societal concern then. A peculiar feature of this old law was the absence of a specific criminal offense for the personal use of cannabis. While possession, unlicensed cultivation, import, and export were strictly illegal and carried heavy penalties, the mere act of consumption itself was not directly penalized. This anomaly often led to public misconceptions and created certain enforcement challenges for authorities, who needed to prove possession to secure a conviction, even if consumption was evident.

"Parts-Based Regulation" and Its Limitations

The old Cannabis Control Act also employed a "parts-based regulation" (bui kisei) system. This meant that only specific parts of the cannabis plant—such as the leaves, immature stems, flower spikes (resin-rich parts), and roots—were legally defined as "cannabis" and thus subject to control. Mature stems (used for fiber) and seeds (used for food or oil), provided they were not processed to extract resin, were generally excluded from the definition.

This system created several irrationalities as scientific understanding of cannabinoids evolved:

• Products containing THC (the primary psychoactive compound) derived from legally unregulated parts of the plant could theoretically fall outside the law's ambit.
• Conversely, products made from regulated parts that contained no THC could still be deemed illegal "cannabis products."
• Crucially, this framework effectively blocked research into and the medical application of potentially beneficial cannabis-derived compounds if they originated from the regulated parts of the plant.

Despite the lack of a specific use offense, Japan maintained a strong societal anti-drug stance, and law enforcement rigorously pursued cases of cannabis possession, cultivation, and trafficking, often with significant social stigma attaching to any involvement with the drug.

The Tides of Change: The Late 2023 Legal Reforms

Several factors converged to prompt a comprehensive overhaul of Japan's cannabis laws, culminating in the passage of the "Act to Amend Part of the Cannabis Control Act and the Narcotics and Psychotropics Control Act" (Law No. 84 of Reiwa 5), promulgated on December 13, 2023.

Drivers for Reform:

• Medical Cannabis Developments Globally: The increasing international recognition and approval of cannabis-derived pharmaceutical products for treating specific medical conditions (like intractable epilepsy) put pressure on Japan to consider pathways for patient access.
• The CBD Boom and Regulatory Ambiguity: The global popularity of CBD (cannabidiol) products led to their import and sale in Japan. However, the legal status of these products, particularly regarding permissible THC levels (as even trace amounts could render them illegal under the old parts-based system), created significant regulatory uncertainty and risk for businesses.
• Emergence of Synthetic Cannabinoids: The rise of dangerous synthetic cannabinoids, designed to mimic THC's effects and exploit legal loopholes, became a serious public health concern. Incidents involving products like "cannabis gummies" containing substances such as HHCH (hexahydrocannabihexol) highlighted the need for more agile regulatory responses. This substance and similar ones were comprehensively designated as "specified drugs" under the PMD Act in December 2023.
• Irrationality of Existing THC Regulation: Under the old system, plant-derived THC was regulated differently (and in some ways, less comprehensively) than chemically identical synthetic THC, which was already treated as a "narcotic" with a use offense.
• Addressing Youth Cannabis Abuse: Growing concern over rising cannabis use among young people spurred calls for more effective prevention and control measures, including clarifying the illegality of use.

Overview of the New Legal Framework:

The December 2023 amendments fundamentally restructured cannabis regulation in Japan:

1. Reclassification of Cannabis and THC as "Narcotics": This is the centerpiece of the reform. Both "cannabis" (defined to include most parts of the plant, including flowers and leaves, but still excluding mature stalks and seeds not intended for psychoactive purposes) and all forms of THC (whether plant-derived or synthetic) are now classified as "narcotics." This brings their regulation under the much stricter regime of the Narcotics and Psychotropics Control Act (Mayaku oyobi Kōseishin'yaku Torishimari Hō, commonly abbreviated as MaKōHō).
2. Establishment of a Cannabis Use Offense: A direct consequence of the reclassification is that the recreational use of cannabis is now a specific criminal offense, punishable under the MaKōHō. Penalties are generally aligned with those for other narcotics.
3. Shift to "Component-Based Regulation" for THC: The regulatory focus moves from controlling specific plant parts to controlling the psychoactive component, THC. This allows for more nuanced and scientifically grounded regulation.
4. Provision for Trace THC Exemption: The revised law includes a provision to exempt products (not in raw plant form, such as oils or edibles) containing THC below a de minimis threshold from being classified as narcotics. This threshold is to be defined by a subsequent Cabinet Order. This aims to address the practical difficulty of achieving 100% THC removal in some derived products, like CBD oil, and to allow products with genuinely negligible THC levels to be legally distributed. As of early 2024, the specifics of this threshold were still under development.
5. Regulation of Precursors (e.g., THCA): The law also allows for the designation of substances that can be easily converted into narcotics (e.g., THCA, the non-psychoactive precursor to THC found in raw cannabis plants) as "deemed narcotics," bringing them under control.
6. Renaming and Refocusing of the Cannabis Control Act: The old Cannabis Control Act has been significantly amended and renamed the "Act on Regulation of Cannabis Plant Cultivation" (Taima-sō Saibai no Kisei ni Kansuru Hōritsu). Its scope is now largely limited to the licensing and regulation of legitimate cannabis cultivation for hemp fiber, traditional uses, and potentially for research or pharmaceutical production. The criminal offenses related to illicit cannabis possession, trafficking, and use are now primarily governed by the MaKōHō.

The Current Legal Landscape: What Businesses Must Know

These reforms create a new, and in some ways clearer, legal landscape, but one that maintains Japan's fundamental prohibition on recreational cannabis.

• Recreational Cannabis Remains Strictly Illegal: The new framework unequivocally criminalizes the recreational use of cannabis, in addition to existing prohibitions on possession, cultivation, import/export, and sale. Penalties under the MaKōHō can be severe and are now generally harsher for cannabis offenses (up to 7 years imprisonment for non-profit related use/possession of narcotics, with higher penalties for trafficking) than under the old Cannabis Control Act (which typically had a maximum of 5 years for possession/transfer).
• CBD Products – Navigating the THC Hurdle:
  • CBD (cannabidiol) itself is not classified as a narcotic in Japan. However, the critical issue for CBD products has always been their THC content.
  • Under the new law, CBD products will only be legal if they contain THC below the forthcoming de minimis threshold to be set by Cabinet Order (or are certified as completely THC-free by highly sensitive testing methods).
  • Businesses importing or selling CBD products in Japan must exercise extreme due diligence. This includes ensuring their products rigorously meet Japanese standards for THC limits, which are typically far stricter than in many other countries. Independent, third-party laboratory testing capable of detecting minute THC levels is essential. Any product found to exceed the permissible THC limit will be treated as an illegal narcotic. The new trace exemption, once its value is set, will hopefully provide more regulatory certainty, but strict compliance will be paramount.
• Synthetic Cannabinoids (e.g., HHCH, "Spice"):
  • Many novel psychoactive substances, including numerous synthetic cannabinoids designed to mimic THC, are proactively designated as "Specified Drugs" (Shitei Yakubutsu) under the PMD Act (Act on Securing Quality, Efficacy and Safety of Pharmaceuticals, Medical Devices, Regenerative and Cellular Therapy Products, Gene Therapy Products, and Cosmetics – Yakki-hō).
  • The manufacture, import, sale, possession, and use of these Specified Drugs without legitimate medical or research purposes are strictly prohibited and carry criminal penalties. Japan employs a comprehensive designation system that allows authorities to quickly ban new and emerging psychoactive substances.
  • Businesses involved in wellness products, vaping liquids, "herbal" incense, or any "alternative" psychoactive products must be exceptionally vigilant about their ingredients to ensure they do not inadvertently contain any banned synthetic cannabinoids. The list of Specified Drugs is regularly updated.
• "Medical Cannabis" – A Very Narrow Pharmaceutical Pathway:
  • A key objective of the 2023 reforms was to create a legal pathway for the development, approval, and use of cannabis-derived pharmaceuticals in Japan. This means that medicines containing THC or CBD (such as those approved in other countries for conditions like intractable epilepsy, e.g., Epidiolex) could potentially be prescribed by doctors and used by patients in Japan, if they successfully undergo Japanese clinical trials and receive regulatory approval from the Ministry of Health, Labour and Welfare.
  • It is crucial to understand that this is not the legalization of "medical marijuana" in the sense of allowing patients to use raw cannabis plant material (flower, crude oils) or to obtain cannabis through dispensaries for medical purposes. The use of unapproved cannabis products for self-medication remains illegal.
  • For pharmaceutical companies, this reform opens a potential, albeit highly regulated and lengthy, route to market for specific, scientifically validated cannabis-based medicines.
• Hemp Cultivation (Fiber, Research, Potential Pharma Source):
  • The cultivation of cannabis plants in Japan (even low-THC hemp varieties) remains under stringent control, requiring licenses issued under the newly renamed Act on Regulation of Cannabis Plant Cultivation. This is primarily relevant for a very small and specialized domestic agricultural sector involved in producing hemp for traditional fibers, shrine uses, and potentially for licensed research or as a source for pharmaceutical production in the future. It is not an area most international businesses will engage with directly.

Implications for International Businesses and Their Employees

The reformed Japanese cannabis laws have several important implications for international companies and their personnel:

• Zero Tolerance for Employee Drug Use in Japan: Companies with operations or employees in Japan must maintain and rigorously enforce clear policies prohibiting the use, possession, or any illegal activity related to cannabis. This is especially critical for expatriate employees arriving from jurisdictions with more liberal cannabis laws, who must understand that those laws have no bearing in Japan. The introduction of a specific use offense further strengthens the legal basis for such policies.
• Strict Product Compliance for Imported Goods (CBD, Wellness, etc.):
  • Any business importing products into Japan that could conceivably contain cannabinoids (e.g., CBD oils, edibles, cosmetics) must undertake exhaustive due diligence. This includes robust testing for THC by accredited laboratories capable of meeting Japan's stringent detection standards. Products must be demonstrably free of THC or comply strictly with the forthcoming de minimis threshold.
  • Marketing claims for CBD and similar products must also be carefully vetted. Making unapproved medical claims can lead to violations of the PMD Act, while misleading consumers about psychoactive effects could attract scrutiny under consumer protection laws.
• Extraterritorial Jurisdiction for Japanese Nationals:
  • The MaKōHō includes provisions for extraterritorial application for many narcotics offenses (though typically excluding simple use by itself if committed abroad by a non-national without other connecting factors to Japan). This means that Japanese nationals who engage in cannabis-related activities abroad that are illegal under Japanese law (even if locally "legal" or decriminalized in the foreign jurisdiction, if those activities would still constitute an offense like illicit trafficking or large-scale possession from Japan's perspective) could theoretically face prosecution upon their return to Japan. While less likely to directly ensnare foreign companies themselves, this underscores the seriousness with which Japan treats these offenses and the global reach of its narcotics control philosophy.
• Supply Chain and Business Partner Due Diligence:
  • Companies should exercise diligence in their supply chains and with business partners to ensure they are not inadvertently associated with any illicit cannabis or cannabinoid production, distribution, or enterprises that are non-compliant with Japanese law if they target the Japanese market.
• Navigating an Evolving Regulatory Environment:
  • The specific value for the de minimis THC threshold in products is a critical detail that was still pending finalization by Cabinet Order as of the time of the recent reforms (late 2023/early 2024). Businesses must monitor official government announcements for this crucial implementing regulation.
  • The list of banned synthetic cannabinoids ("Specified Drugs") under the PMD Act is also dynamic and regularly updated by the Ministry of Health, Labour and Welfare. Continuous monitoring of these regulatory updates is essential for compliance.

Beyond Criminal Law: Societal Attitudes and Workplace Culture

It is also important for international businesses to recognize that, beyond the strict letter of the law, societal attitudes in Japan towards cannabis and other illicit drugs remain overwhelmingly negative and condemnatory.

• Despite shifts in some parts of the world, cannabis use is highly stigmatized in Japan.
• Any drug-related incident involving an employee, even if minor from a legal perspective in another country, can lead to severe and lasting reputational damage for a company in Japan. This can affect customer trust, business relationships, and employee morale.
• Therefore, fostering a workplace culture that unequivocally respects Japanese laws and deeply ingrained societal norms regarding illicit substances is a critical aspect of risk management and successful, sustainable operations in Japan.

Conclusion: Navigating Japan's Cannabis Laws Requires Vigilance and Absolute Clarity

Japan's recent comprehensive reforms to its cannabis legislation have sought to modernize and rationalize its approach, notably by criminalizing use and creating a regulated pathway for potential cannabis-derived pharmaceuticals. However, the nation's fundamental stance remains one of strict prohibition against recreational cannabis and tight, centralized control over all related psychoactive substances.

For international businesses, the message is unambiguous: the regulatory environment concerning cannabis in Japan is far from "hazy" in its core prohibitive intent. Thorough due diligence regarding product composition (especially THC levels in any cannabinoid-containing products), strict adherence to the evolving specific regulations (such as the forthcoming THC trace thresholds and the list of banned synthetics), and clear, consistently enforced employee policies are paramount. Navigating this landscape successfully requires ongoing vigilance, expert legal counsel, and an unwavering commitment to compliance to avoid significant legal, financial, and reputational pitfalls in the Japanese market.