In Vietnam, people must belong to one of the 54 ethnic groups recognized by the state. In the agricultural hilly area in the north, nearly 100,000 people are self-proclaimed Ngai, who speak a kind of Hakka language. Though the state accommodated the new category ‘Ngai’ to pull them apart from China during the Chinese-Vietnamese War in 1979, the cadres in the rural area compelled the Ngai people to register themselves as Hoa, as they regard the people with Chinese-origin as Hoa. According to the Statistics Bureau of Vietnam, only around 1,000 people are recognized as Ngai. In this study, I consider the difficulty faced by one ethnic group to live in country A, which conflicts with country B, to which they originally belong. To this end, I clarify the life histories of the self-proclaiming Ngai. They are publicly regarded as reactionary in nature, but many Ngai cooperated with the Viet Minh and did not leave Vietnam even in 1978-79. As discriminatory policies were implemented without public knowledge, the Ngai faced severe hardships in the 20th century. Recently, however, the young Ngai are pioneering their way to a better life by going to work in China, using the new network that was established during the war.