Sometimes, there are front or main shrine and a back shrine in a Japanese shrine. In many cases, a back shrine is Powerfull or Mysterious to a front shrine. "Okumiya" or "Okuin" is that back shrine or temple. I guess Shrine cases call "okumiya", Temple cases call "okuin". This "Mitsumine-jinja" Shrine call "Okunomiya". Sometimes there called "okunomiya", or "okunoin". Entrance "Okumiya" It's First "Torii"(The Gate to Shrine) Second "Torii" Third "Torii" Fourth and Last "Torii"