1. Tourists Must Carry The Passport With Them All The Time
Japan law has given permission to the police to stop anyone in any given time to identify him. Because of that tourists must have their passport at all time so they can show their identity, so if you are without passport you can be arrested.
2. Certain Medicaments That Are Legal In The Whole World Are Illegal In Japan
Japan allow foreigners to bring 2 months supply of their medicaments that they need. But there are a lot of medicaments that are forbiden and its very difficult to figure this out, so make sure you have a doctor note for the medicaments you use.
3. Smoking Is Allowed In All Coffee Shops And Restaurants, But Not Outside
Smokers in Japan had the privilige to smoke almost everywhere, outside and inside, and because the tobbacco is cheap smoking was very spread out among the people. But not that long ago the law was changed, so outside was not everywhere allowed to smoke, and inside there are designated places where you can smoke.
4. Drinking On The Street Is Allowed In Japan
Unlike everywhere else drinking on the streets and public places is allowed. There are even vending machines where you can buy beer or sake, but still even if you drink outside like in a park or on the beach you have to act respectfully.