Australia BCOF 1946-47 3d purple-brown error opt double, SGJ3aAustralia British Commonwealth Occupation Force 1946 47 3d purple brown, error OVERPRINT DOUBLE, SGJ3a. A fresh mint example of this rare error with large part original gum, (a little disturbed by hinge removal). These stamps were used by the Australian forces occupying Japan after the Second World War. Initially their post offices supplied unoverprinted Australian stamps, but it was decided to introduce the overprinted issue to prevent currency