Japan Rail Pass
The Japan Rail Pass allows you to use any Japan Railways (JR) services for a specific number of days, depending on the amount of money you pay. Only foreigners visiting Japan on a 90-day tourist visa can purchase a Japan Rail Pass. The pass cannot be used for the new super express Nozomi Shinkansen service, but is good for everything else (including other Shinkansen trains), and the only additional surcharge levied on the Japan Rail Pass is for overnight sleepers. This pass is acquired by purchasing a voucher from travel agencies before leaving the United States, and then the rail pass is redeemed in Japan. The clock starts to tick on the pass as soon as you validate it, which can be done at certain major railway stations or at the JR counter at Narita or Kansai Airports if you are intending to jump on a JR train immediately. The pass is valid only on JR services; you will still have to pay for private railway services. See http://www.japan-guide.com/e/e2361.html for more information.