Near Muang Sing, in a Mien (Yao) village, woman with baby and child

The Yao nationality (its great majority branch is also known as Mien) is a government classification for various minorities in China. They form one of the 55 ethnic minority groups officially recognized by the People's Republic of China, where they reside in the mountainous terrain of the southwest and south. They also form one of the 54 ethnic groups officially recognized by Vietnam. In the last census in 2000, they numbered 2,637,421 in China, and roughly 470,000 in Vietnam.

The typical houses of the Yao are rectangular and they have structures made of wood and bamboo. Normally it has three rooms: a room and two dormitories in the lateral side. Each one of these rooms has a small oven to cook.

The men and the women cover their heads with a black or red scarf. Some women substitute this scarf by a turban that can adopt different forms. The traditional suit of the women is of bright colors. They also decorate their shirts with decorations made out of silver.

Muang Sing or Mueang Sing is a small town and district (muang) in Luang Namtha Province, northwestern Laos, about 60 kilometres northwest of the town of Luang Namtha and 360 kilometres northwest of Vientiane. It lies in very close proximity to the border with Yunnan, China, surrounded by mountains and rivers. Historically Mueang Sing has been a major producer of opium and still has problems with drugs and smuggling, due to its geographical position in close proximity to China and Burma.