JNR passenger services divisions were broken up into: JR Hokkaido, East, Tokai/Central, West, Shikoku, and Kyushu. Of those:

  - JR East took the whole east half of Honshu from southernmost end of Tokyo area all the way to Aomori.
  - JR Tokai aka Central got just Nagoya area + later the entirety of the Tokaido Shinkansen, Tokyo to Osaka.  
  - JR West got the whole Osaka area and to the west of Honshu. 
  - JR Hokkaido, JR Shikoku, JR Kyushu got one giant island to themselves each.  

This means Tohoku Shinkansen rails and services going from Tokyo to north is on JRE rather than under Tokai/Central. And the Smart EX system mentioned in GP is a service offered by Tokai/Central, so they don't do JRE trains. uhhh same JR different company. Except when the system works. Then they are happy to issue any tickets they can. Bureaucracy!