Vietnamese practice of avoiding tabooed names and its expressions found in Vietnam’s Sino-Nom texts, which consists of texts written in the classical Chinese language and those in Nom, belong to a tradition that began in the Tran dynasty (the 13th century). There are three kinds of expressions of tabooed names in Sino-Nom literature: (1) lowercased annotations written in the place of the (unwritten) tabooed name: this type is very rare, only found in the documents of the 13th and 14th centuries; (2) a blank in the place where the tabooed name should have been inserted: this method is also very rare, only appearing once in a 15th century document; (3) modified forms of the character that represents the tabooed name: this is the main method of avoiding tabooed names of ancient literature. Because Chinese characters are built using different radicals and strokes, the omission or separation of them in order to modify the character into a new variant is easy. There are four modes: (3.1) the omission of strokes: this mode can be further divided into even more specific varieties which are the simple variety of characters with missing strokes, the variety of characters with missing strokes and an added circle-shaped mark, and the variety of characters with missing strokes and added components; (3.2) dividing and flipping of the characters: in this mode, the character is divided into two halves, left and right, or lower and upper, and each half is flipped to face the opposite direction, the “ 兩腳”, “two-footed mode”, so to speak; (3.3) the addition of new components regardless of whether or not their shapes are flipped or reversed; (3.4) variants with forms very different from those of “normal” characters. Each type of those mentioned above exists in even more varieties. The first two were mainly used in the 13th and the 14th centuries, when the practice of avoiding tabooed names just began to appear. The third type was mainly used in the 16th and the 17th centuries. After each dynasty, the practice as such became ever more important, and thus also more reliable as an indication to determine the date of each specific Sino-Nom text.