Lockout laws in Japan?

I'm currently 18 and I'm looking to go to Japan with my friends at the end of the year. I heard that there are lockout laws for people under 20 years of age? Can anyone help me out on this as I don't want to go there for no point. Thanks!

What is a lockout law?

Do you mean for purchasing alcohol? 18 year olds are prohibited from purchasing alcohol, but in practice the checks are only cursory if performed at all.

I don't know what a lockout law is either but the first thing that came to my mind when I read this was the curfew for minors. If that is what you are talking about it does vary depending on city/prefecture so you will want to check local laws. I believe in Tokyo (Kawasaki and Yokohama too?) under 18s are forbidden from being out after 11 p.m. In truth there really shouldn't be any problems for you, I don't think you would find these laws being enforced on foreign tourists very often. More trouble than it is worth for the police, I would expect they are only likely to bother with school uniform-wearing Japanese kids wandering around in the middle of the night.

"Lockout laws" usually refer to bars/clubs/etc. not allowing entry to anyone after a certain time (usually early morning) to encourage people to reduce their drinking and/or go home.

What you're looking for is just entry laws; i.e. can you enter a bar/club/etc. if you are under the legal age limit.

I believe age restrictions depend on the individual bar/club/etc. If you've got specific places in mind, look them up beforehand. But be careful drinking just in case you do get carded; getting in trouble overseas is always a nightmare. I've heard that on the whole underage drinking and smoking are overlooked a lot in Japan, but that doesn't mean you should take the risk.

I see, looking into it more it seems it's an Australian term referring to what sq describes.

Bars and restaurants in Japan are generally not very strict. Unless you look particularly young, they are probably not going to refuse you service. Clubs, on the other hand, tend to be strict with carding, and I probably wouldn't bother trying to go.

Depends on the location, as discussed here:
http://www.japan-guide.com/forum/quereadisplay.html?0+47367

As suggested, if you're already 18 there shouldn't be any problem. The 11pm by-laws are for 17 years old and younger. They can't sell late night movie tickets to those minors, and things like that.

Just keep in mind that the police does have the right to politely ask you to go back to your hotel if you're under 20 and obviously fooling around after the last train. This usually doen't happen as long as you behave like an adult.

Depending on where you are staying, especially if it's at a youth hostel, you should also check if they have a curfew as well. A lot of hostels will lock their doors at 11pm and refuse entry until the morning. That may have a lot to do with local youth curfew laws.