Thanks nvubu and I have to declare Open House. You provided a few super clues, without which I'd never have been able to get near a solution. Six hours from Guam and the usual cargo back and forth could have applied equally to Yokinawa or Manila. I wasn't too sure abut my dates - Okinawa v Philippines - but suspected that extraction of the wounded to Guam would more likely have been from Japan's islands than from SE Asia.
After posting Yontan I went back to Gurgle and had a great disappointment: searched for "C54 Yontan" and came up with a derivative of your image challenge. Which of course knocked all the air out of awaiting your confirmation or not of my earlier guess.
Again< Open House