It is also convenient to go by JR train. Currently, it
is necessary to change to an express train when using the
Shinkansen, but extension of the Shinkansen line to Sapporo
in the future is being considered. As well, there is a direct
sleeper car train from Tokyo and Osaka which are both very
popular. In particular, the Cassiopeia has such well-appointed
facilities that it is called a "moving hotel".
The JR pass for foreigners traveling in Japan is a good deal
(Japan Rail Pass, Hokkaido Rail Pass and Sapporo/Otaru Welcome
Pass, and so on). Charters and special trains are also possible.