Can I hitchhike in Japan?

So I have hitchhiked once when lost on a mountain road two hours in the wrong direction when I was with a friend. But besides that, I don't have much experience.

Is it safe? Is it legal? What's the best way to do it? I want to hear your experiences.

I am thinking of trying it some more. 

As a woman, I think I will never try, but...

WikiTravel says that

...you have to find the places where drivers going out congregate, which in practice means service areas (サービスエリア sābisu eria, SA) or parking areas (PA) on the large toll expressways (高速道路 kōsokudōro) connecting Japan's major cities. As you might guess, service areas are larger and better equipped than parking areas (with the special exception of Mekari/Dannoura, see below), but surprisingly few Japanese are familiar with the difference so it's easier to label them all service areas.

http://wikitravel.org/en/Hitchhiking_in_Japan

Yes, you can hitchhike in Japan and it's incredibly easy. I tried it a few times with a friend and we were picked up almost instantly - I think the longest we had to wait was about ten minutes. Think about how hospitable most Japanese people are: they're exactly the same when driving! You'll probably find people will go out of their way to take you to your destination, they may buy you food and drink, and they almost definitely won't accept any petrol money.

There's a good article on hitchhiking here. I'd also recommend the book 'Hokkaido Highway Blues', by Will Ferguson. Although it's a few years old (pre smartphone days!), it's an amusing and interesting read, about a guy who decided to follow the sakura and hitchhike the length of Japan.

In response to Olga's comment, obviously people should only do what they are comfortable with, but I don't think that just because you're a woman you should rule out hitchhiking. Whilst I never hitchhiked on my own, a good female friend of mine spent a week or so travelling around western Japan, camping and hitchhiking the whole time, and she had an amazing trip. Everyone who picked her up was very friendly and curious, and she said some people even invited her to stay with them as they didn't understand why she wanted to camp! Of course, if a situation doesn't feel safe then you should trust your instincts, but I think that of all the countries in the world, Japan is probably one of the best for women to hitchhike in.

I've hitched quite a bit in Japan. It's quite easy here and a great way to meet people. Just be careful not to obstruct traffic, cause annoyances, etc. Use common sense that you would hitchhiking anywhere else.

If you're familiar with car sharing websites such as mitfahrgelegenheit.de in Germany and www.carpooling.com in the UK, where drivers can offer spare seats on journeys they are making, there is a similar website in Japan too - notteco.jp. Unfortunetely it's in Japanese though. I see they've recently revamped they're website though so hopefully an English version is in the pipeline. I haven't used this website myself but I have in other countries and it's a great concept. Kind of like couch surfing, but for finding a lift :)

Yeah, I heard alot that hitchhiking in Japan is doable and quite easy. But, I think it's better if you speak some Japanese.

Yes. My Japanese Language classmate (American male) did it over 12 days and he was able to visit so many places including Fukuoka, Kyoto, Nara, Osaka etc. for free. He did say that some of his rides were from people he met at the public baths and the inns he stayed at. I guess he was good at chatting with them and making friends and asking whether he could hitch a ride. I don't know how much of his hitchhiking was from standing on the road with a sign. Japan is probably one of the safest places to hitchhike. My classmate said he would not do this in the US. 

I've heard great things about hitchhiking in Japan! It's probably the only place I would feel safe doing this, as a woman. 

If you are a foreigner, there won't be any problem because Japanese would understand the culture difference, though, most Japanese avoid hitch-hiking because of these common reasons: 1. They are too shy to say so. 2. It is in their culture to avoid asking any favor that they feel would inconvenience another. And 3. They just want privacy. Japanese would rather pay to get a space of their own on the transportation. 

And while it is safe to hitch-hike in Japan, it is best to know the person you will be hitch-hiking. So being able to talk to them for more than 5 minutes to get a short and quick glimpse of who they are would be safer than getting on the car without having any idea what they are like. Being cautious is still better then being sorry even if this is Japan, because we do not know what may happen along the way.

I hithiked in Japan in 2004 and went from Naruto station to the beach.  I wasn't able to get a ride back an I was late for work.