In response to the Khmer Rouge's cross-border offence, Viet Nam launched a full scale invasion of Cambodia in late 1978.
During the invasion and occupation period which last for a decade, most Vietnamese combatants in Cambodia wrote home using the Vietnamese military mail service. Mail was taken from Cambodia to southern Viet Nam by pouch and then returned to the Vietnamese mail stream for delivery. The following is a sample of it.
In the return address "HT" stands for "Hòm Thư", "PO Box" in Vietnamese. "7A" indicates that it is from Tactical Zone #7. Not all Tactical Zone #7 mail was from Cambodia, so it is vital for collectors to find further information for clarification. For this cover, the acronym "C.P.C." which stands for "Campuchia" in Vietnamese is the clue that tells the sender's location. It was discouraged to include geographic names in the return address, this sender was simply a rule breaker.
While the vast majority of Vietnamese military mail from Cambodia was postmarked in Saigon of Viet Nam, this mail was in Mỹ Tho. Mỹ Tho, capital of Tiền Giang Province, is a Mekong Delta region city located 70km from Saigon. The cover has two strikes of the Mỹ Tho postmark yet no stamp franked when I acquired it, the stamp might have fallen off if there ever was one, I tend to conclude that it has no stamp as no paper thinning is observed. The date shown on the postmark is 26th July 1979.
Another Mỹ Tho postmark appears on the back of the cover, but dated one day after, 27th July, 1979.
The cover is roughly made with lined writing paper, not a surprise as in those days everything was in shortage in Cambodia and Viet Nam.