The "ao dai" ("flowing tunic") has been the traditional dress for Vietnamese women long, long ago. There are many different kinds of ao dai: the four-part flowing tunic had two equal front flaps that women tied together, while the five-part flowing tunic had an additional small front flap that buttoned up onto the right side of the dress.
Different regions of the country have their own styles of flowing tunic. In the north, Vietnamese women usually wear the four-part flowing tunic, refers to as "Ao Tu Than", with a long skirt. The hat is called "Non Quai Thao".
On the right, instead of wearing "non quai thao", Nothern women just simply wear a scarf as a variety.