Khau Vai is located at Ha Giang, about 24 kilometers from the Central Highlands of Meo Vac. 155 kilometers long and situated on a hill, it is said to look like a rope, even a snake, along with its bumpy mountains, steep cliffs, foggy peak and slippery dirt road.

Instead, it's a place where old couples, that is, used-to-be, meet up with their once partners in a sort of rendezvous because it is no longer possible for them to get married being married to other people themselves. This includes both young and old couples, covering all ages.

When the market opens at night of the lunar month, husbands and wives arrive at the market together but soon split up to look for their former lovers. Women from the Giay ethnic minority and men from the Hmong community bear walking up to three, even four, days, just for this rare opportunity to be able to rekindle their old relationships.

The market opens only once a year, from late evening of lunar March 26 until late morning of the next day.