Japan has some of the strictest customs and import laws in the world, and violating them can lead to immediate deportation or arrest. Prohibited items include all forms of illegal drugs, including some that are legal elsewhere, such as CBD oil with detectable THC or certain prescription stimulants (like Adderall) containing amphetamines without a prior "Yunyu Kakunin-sho" certificate. Firearms, ammunition, and explosives are strictly banned. In terms of food, Japan has extremely rigorous biosecurity laws: you are generally prohibited from bringing in most meat products (including jerky and ham), fresh fruits, vegetables, and plants from most countries unless they have a phytosanitary certificate, which is rare for travelers. Counterfeit goods, such as "knock-off" designer bags or watches, are also subject to seizure. Furthermore, bringing in "obscene" materials, including certain types of adult media that violate Japanese censorship standards, is illegal. Always check the official Japan Customs website if you are carrying specialized medications to ensure they are not classified as controlled substances under the Narcotics and Psychotropics Control Act.