The Ao Dai (pronounced Ow Zhai), literally meaning "long dress" or "long tunic" is one of many traditional Vietnamese costumes worn (nowadays) most often by women. It is the national costume of the Vietnamese people.
In the 1930s, the Vietnamese fashion designer Cat Tuong, known to the French as Monsieur Le Mur, modified the Ao Dai from the Ao Tu Than. They lengthened the Ao Dai so that the tunic reached the floor, and made it fit the curves of the body more closely. With the import of a range of foreign fabrics in 20th century Vietnam, including broader fabric, the modernized Ao Dai required less material and as a result, the flaps of the tunic became generally narrower.
In Saigon during the 1950s, Tran Kim of Thiet Lap Tailors and Dung of Dung Tailors modified the Ao Dai to a form closer to what we see today. He made the gowns with raglan sleeves, creating a diagonal seam that ran from the collar to the underarm.
The Ao Dai continued to become more form-fitting over time.
In the 1960s the collarless Ao Dai style was popularized by Madame Nhu (former first lady of South Vietnam).
Despite the two major modifications to the Ao Dai in the 20th century, it has also seen slight changes throughout each decade as fashion changes constantly. Everything from floral to checkered patterns, the use of transparent fabrics, the tunic length being shortened or lengthened, has all been seen throughout different eras of Vietnamese history.
The Ao Dai has always been more prevalent in the south than in the north, and has faced a surge in popularity in recent years, even with overseas Vietnamese.
In recent decades it has inspired worldwide renowned fashion designers such Chanel and Ralph Lauren, among other big names, to create entire collections of Ao Dai.
The most popular style of the Ao Dai as we see it today is tight-fitting around the wearer's upper torso, emphasizing her bust and curves. For this reason, the Ao Dai, while it covers the whole body, is said to be provocative but elegant, especially when it is made of thin or see-through fabric. The Ao Dai covers everything but hides nothing!