this one is interesting, when it was sent out from Shanghai on 3/12/41, it was treated as an airmail with postage due at 40 cents (360-320), but before it arrived in HK, the Pacific War had started and it had no chance to get on HK, or maybe it got on HK 8/12/41 , and then the postage due was crossed off as the airmail was crossed off, but we don't know how it got to Calcutta, throught rangoon or from Kunming