The Yao ethnic community in Mau Son Commune, Lang Son Province in northern Vietnam is well known for hosting betrothals in the dead of night. 

Duong Hoa, sitting between two bridesmaids, enjoys a meal at 11 p.m. before visiting the house of future partner Hoang Dau Huong in Cong Son Commune of Cao Lac District. 

Lensman Nguyen Son Tung, a Lang Son Province resident and author of this series of photos, has spent much time learning about the traditonal customs of the local Yao ethnic group in Loc Binh District's Mau Son Commune.

Mau Son, situated amid a range of nearly 80 mountain peaks, is home to a population of mainly Yao, as well as Tay and Nung ethnic minorities. 

Yao weddings are particularly unique, taking place in the late night.

Local Yao believe all that is good is born while the sun still sleeps. It is usually up to a shaman to decide when a bride can enter her groom's home.

Brides typically leave home at 2 a.m., dressed in one embroidered outfit, and enter their groom's house at 3 a.m., dressed in another while the entire village remains caught in slumber. Dowries form an additional part of proceedings.

The bride’s family usually stops 300 m from the groom's house to help the bride change into her second outfit, adorned with necklaces and bracelets.

At the appropriate time, the bride, her face covered by a hat, is escorted inside by the bridesmaids.

"The light emitted from the groom's house creates a cozy feeling amid the cloudy atmosphere and the quiet night," Tung said.

The ceremony to welcome the bride is grand, with a team that plays trumpets and relatives lining both sides.

The groom places 12 pairs of chopsticks, 12 bowls and 12 cups of wine on the altar to pay respect to ancestors and family.

According to Yao custom, the groom is not allowed to see the bride's face until the rituals are performed. This tradition serves to avoid bad luck.

After the shaman completes the rituals, relatives provide wine, poured into a cup, placed on a rice sieve and drunk in gratitute. Each person is offered a cup of wine with a piece of boiled pork liver to celebrate the union. 

At the end of the ceremony, the groom's family provides a big music-filled feast that can last up to 4 a.m.

Such ceremonies also give the elderly and opportunity to recall their vibrant youth. Previously, Yao weddings, involving many rituals, could last three days and three nights. Nowadays, they are shortened to only one.