Strange how movies evoke such reactions from CB community.
Miyagi is not an uncommon name in Japan. It is the name of one of Japan's prefectures, in the northern region of Honshu, known as Tohoku, which one includes Fukushima, where the 2011 tragedy occurred.
I lived in Okinawa's 'Miyagi' section for 3 years, just outside Kadena's Gate 4. It looks though that Gate 4 has been renumbered now as Gate 3.
The LDS branch in that area was called the Gushikawa Branch.
There is a new LDS chapel very close-by, less than 1km to the East on North side or Rte 74.
A most popular 'dive' but best-ever Mongolian BBQ was to be had near Toguchi Beach, which is to the NW side of Kadena.
Two of my children were baptized in the East China Sea at Toguchi Beach.
Yoroshiku -