Okinawa | Finding my great grandpa's house in Okinawa 

You should try asking all the old neighbours near to that house, somebody will know if there is a connection in family names. The writing on the wall (3:19) is an "Ishi gan tou" plaque. These are placed there, or sometimes written in the concrete, to divert any evil spirits from the house. The holes cut into the walls are often tomb entrances. Inside they will have small boxes containing the bones of ancestors. Good luck in your search. You could also try the local town hall - they may have documents on who lived where, if they survived the war.