Móng Cái is a city of Quảng Ninh province in the Northeastern of Vietnam. Its name Móng Cái originated from Cantonese language, meaning "t…Móng Cái is a city of Quảng Ninh province in the Northeastern of Vietnam. Its name Móng Cái originated from Cantonese language, meaning "the mong market". It generalized the situation of the population in this beach in the Middle Ages, when the groups Nùng, Tày and especially Tanka lived together.