Japan's Oldest Castle by Date
Akita Castle (then called Dewa-no-ki or Ideha-no-ki) was established in 733 AD — making it the oldest castle in Japan by historical record. Built as an imperial frontier garrison to control the Emishi and Mishihase peoples of the Japan Sea coast, it predates the castles of the samurai age by over 700 years. This is where Japanese civilization reached westward Tohoku.