The Sino-Vietnamese War ( ; ) , also known as the Third Indochina War , was a brief border war fought Hostile_encounter between China and Vietnam in early 1979 .

Following the dissolution of the Soviet Union in 1991 , the Sino-Vietnamese border was finalized .

The Sino-Soviet split re-emerged Coming_to_be following the lull during the Vietnam War and conflict between North Vietnam and its Cambodian allies in the Royal Government of the National Union of Kampuchea , and the newly-formed Democratic Kampuchea begun Process_start almost immediately in a series of border raids by the Khmer Rouge that erupted into the Cambodian–Vietnamese War , with Chinese forces directly invading in the Sino-Vietnamese War and subsequent border conflicts .