Meo Vac is a mountain pass at about 1,5km elevation which forms the basin boundary of the Nho Que River on the border with China is restricted zone. The market held at Khau Vai which is about 20km from Meo Vạc, is where once a year on the 27th day of the third month of the Lunar calendar is known famously as the Khau Vai “Love Market”. The ethnic clans of White H'Mong, Tay, and Lo Lo congregate here, particularly the young people assemble here in search of life partners or to exchange partners.