Nhan is a Vietnamese word for longan. The longan grows in many provinces in the North of Vietnam. The longan is no bigger than a ping-pong ball with brownish peel. The peel only has to be slightly removed to reach the whitish pulp, enclosing the glistening black kernel.
There are many known varieties of longans in Vietnam. The most renowned variety of longan is the cage longan of Hung Yen Province. There are varieties that have a thick pulp and a very sweet taste called pulp longan. Water longans have a thin watery pulp and a fresh sweet taste. In the South, there is the longan of Chau Thanh (Dong Thap Province), which is fairly renowned. This variety has a watery pulp, a very sweet taste, a perfumed scent, and small black seeds, which is why it is called nhan tieu (pepper grain longan).
The longan is a tropical fruit rich in nutrients. It is used in the preparation of sweet lotus seed soups. A longan that has been rid of its black kernel then dried over a fire is called long nhan which literally means "dragon’s eyes" which is one of the tonics used in the recipes of traditional medicine.