If you are arriving by Shinkansen, it is usually quicker to change from the Shinkansen to the Tokaido line at either Nagoya or Toyohashi rather than at Mikawa-Anjo - even though Mikawa-Anjo is closer. The reason for this is that Mikawa-Anjo is in the middle of nowhere (the location of certain shinkansen stations can best be described as the result of political interference). If you take the Hikari (express) it is best to change at Nagoya. You should really only use Toyohashi is you are arriving from the east by Kodama (all stations).