So you want to go to Japan? Come on over! People are helpful. Roads are in good condition. And costs are not as high as you think.
As far as I know, there are two ways in. Shipping your bike by sea or air from wherever. Or taking the ferry from Russia.. One ferry runs from Vladivostok to Fushiki-city (Toyama prefecture). The other way is from Sakhalin island in Russia to Wakkanai city in Japan. However, I haven't taken the Sakhalin ferry to Japan and don't know anyone who has. There is talk of opening up the ferry to and from South Korea. But currently the Shimonoseki - Pusan ferry will not take motorcycles. And Korea bans temporary imports of personal motorcycles.

We get about five or six overland bikers a year. Not much compared to some countries. But Japan is mostly used as a stopover to or from Russia. Most of the riders passing through say they enjoy their stay in Japan. If you want to joint them in being a visitor to a friendly--albeit slightly expensive--country, browse on!

Please let me know if you find any mistakes in this site or have any further questions.
If you want to meet other motorcycle travelers when in Japan, contact the World Touring Network-Japan .

For other motorcycle travel related information, go to...
Horizons Unlimited World Motorcycle Travel:
http://www.horizonsunlimited.com/index.shtml