While my class was in Japan we rode the Shinkansen (Japanese for New Rail Line) between the cities we stayed at. We rode the entire New Tokaido Line (between Tokyo and Osaka) and most of the New Sanyo Line (between Osaka and Hakata). The New Tokaido Line is the oldest high speed rail line in the world, opening for service in 1964. The New Sanyo Line was opened in 1975 and was built for higher speeds. Trainsets used on these lines include the 100-series, 300-series, 500-series, and 700-series. A handful of 0-series trainsets also operate on the New Sanyo Line in Kodama service. There are three types of service provided on the southern Shinkansen routes. The slowest is Kodama service, which is all-stops local trains. Next is Hikari, which is express service, with trains skipping some stations. The fastest is Nozomi, which is limited express service, with trains only stopping at the most important stations.  The northern routes have different names for the various classes of service.
As a result of the breakup of Japan National Railways, the New Tokaido and New Sanyo lines are run by two different companies. JR Central runs the New Tokaido Line, while JR West runs the New Sanyo Line. Both companies cooperate on run-through trains that cover the whole distance between Tokyo and Hakata.