The traditional writing of the Vietnamese nation – Nom characters – is a kind of “Sino style” (or so called “Chinese-character-shaped”) “square-shaped” writing system. For more than 100 years, many Vietnamese and foreign scholars have been interested in this writing, discussing and engaging in studying it from different angles. Starting from the philology point of view, the author tries to reveal the issues surrounding “Nom character” studies. They can be attributed to three big topics: 1. The origin of Nom characters and how it became a writing system lasting throughout different historical periods; 2. The internal structures of Nom characters and their evolution; 3. Different stages of Vietnamese philology and the social functions of “Nom characters”. This paper is going to discuss the above-mentioned topics, at the same time as introducing some of the authors’ observations on these topics as references for colleagues.