The Socialist Republic of Vietnam is a country on the south eastern tip of mainland Asia. With a population of just over 90 million, it is the 13th most populous nation in the world.
Flag of Vietnam
Vietnam's history from the first millennium is very much intertwined with China, with the Chinese Empire effectively ruling Vietnam as a province. Vietnam's independence was secured at the Battle of Bach Dang River in 939 AD. Vietnam's territory was limited to the northern Hanoi region, but over the next 7 centuries the south was conquered in phases. The southern tip of Vietnam, the Mekong Delta, was part of the Khmer Empire and even today is home to ethnic Khmer which are related to Cambodians.
The French started their fiest missionary posts in Vietnam in the 17th century, but from the 1850's actual colonisation of Southern Vietnam started with the colony of Cochinchina. By the start of the 20th century the French had expanded their territory to entire Vietnam, Cambodia and Laos by fighting wars against Siam, China and the Vietnamese Empire. The result was French Indochina, which lasted until the early 1950's.
During WW2 French Indochina fell under Vichy and Japanese influence. A communist/nationalist insurgency, backed by the West, was led by Ho Chi Minh in an effort to drive the Japanese out. Ho Chi Minh's ambitions led to a declaration of an independent Vietnam in 1945 but the French intervened in 1946 starting the Indochina War or First Vietnam War. The French were humiliatingly defeated by the Vietnamese at the Battle of Dien Bien Phu in 1954, which led to the Geneva accords recognising the socialist North Vietnam and a West-aligned South Vietnam.
Flag of South Vietnam
The partition of Vietnam was not intended, but a referendum for reunification was blocked after a coup in South Vietnam. Pro-Hanoi rebels founded the Viet Cong and started the Second Indochina War or Vietnam war. North Vietnam supported the Viet Cong, and over the years this conflict evolved into a Cold War proxy conflict with an active US intervention and passive support by the USSR. The Vietnam War was basically an independence struggle misconceived by the USA as a communist-inspired expansion in South East Asia. The results were tragic: millions of Vietnamese died, and so did 60,000 US soldiers leading to many protests in the West and a damaged US reputation. In 1974 Nixon retreated and a year after North Vietnam was victorious in capturing the South Vietnamese capital Saigon.
Vietnam was reunified as a socialist state backed by the USSR rather than China, as the Vietnamese trusted the Chinese less in their intentions. From 1990's Vietnam has reformed its plan-based economy and from 1995 its relationship with the USA was reestablished. The Vietnamese economy has since been growing fast, but it's still a developing nation.
Recently tensions with China have erupted over territorial claims in the South Chinese Sea. It is starting to look like Vietnam is becoming more US-aligned than people ever held realistically possible.
Currency
The Vietnamese Empire used copper cash coins (similar to Chinese) and silver coins denominated in Tiên. A Tiên was around 3 to 4 grams of silver and 7 Tiêns was almost equal to the Spanish 8 Reales or Peso, which became the most used silver coin in Asia from the 17th century. When the French came the cash coinage was continued, but modern coinage was introduced in the form of the French Indochinese Piastre which was equal to the Peso and worth 500 to 600 Cash. Also Tiên coins stayed in use.
In 1945 the newly proclaimed Vietnam introduced the Dong at par with the Piastre. It was subdivided in 10 Hao each of 10 Xu. This currency was named the 'Rebel Dong', with the Piastre still the official currency. After full independence in 1954 both Vietnams introduced their own Dong at par with the Piastre. The Southern Dong was replaced by the 'Liberation Dong' after the fall of Saigon in 1975 for 500 old Dong. In 1978 both Dongs were unified into a single currency where 1 Northern Dong equalled 0.8 Southern Liberation Dong.
In 1985 the Dong was redenominated at 10 to 1, but chronic inflation persisted. It is now the second least valued currency in the world with an exchange rate of 22,000 Dong per USD.
Coins
Modern Vietnam coins use the Roman script which makes them easy to identify. If the coins consist no communist symbols it's from South Vietnam from before 1975.
South Vietnam issued various types of 10, 20 and 50 Xu and 1, 5, 10 and 20 Dong. The Liberation Dong consisted of holed aluminium 1, 2 and 5 Xu with legend 'Ngan Hang Viet Nam'.
North Vietnam had its first coins in 1945 when the rebels declared an independent Vietnam, but these were only used in rebel-held territories. After official independence in 1954 a new series was issued of 1, 2 and 5 Xu in 1958, with 1, 2 and 5 Hao and 1 Dong added in 1976.
The second Dong had no coins until 2003, when denominations of 200 to 5000 Dong were issued after chronic inflation had seriously reduced the value of the currency.
Vietnamese empire:
https://en.numista.com/catalogue/vietnam-empire-1.html
Vietnam (including North):
https://en.numista.com/catalogue/viet_nam-1.html
South Vietnam (1954-1975):
https://en.numista.com/catalogue/south-vietnam-1.html