The name given to the Annamese rectangular silver bars introduced under the Emperor Ngaien-tschung (1802-1820). They are supposed to equal in weight the native ounce, called Lu'ong, and are consequently frequently referred to as Lu'ong Bae. See Fonrobert (2097, 2105). There is a half of similar shape.
Source: Frey's Dictionary (American Journal of Numismatics, Vol. 50, 1916)