Abstract
The ancient site of Hoa Chau citadel now confined entirely within the area of 3 villages including Thanh Trung, Kim Doi and Thuy Dien of Quang Thanh commune, Quang Dien district, Thua Thien Hue province. As early as the sixteenth century, this citadel was addressed by Duong Van An in O Chau Can Luc. Since then, many attempts have been made to study the Hoa Chau citadel, however the scope and structure of the citadel still not yet to be determined accurately and especially the date and owner of this citadel are still unclear.
Thus, in the research agenda of Hoa Chau citadel from 2007 to 2012 between the History Department, Hue University of Sciences and Kansai University (Japan), in which the late Dr. Nishimura Masanari was the representative, the most important issue posed was the need to determine the scope/size, structure and characteristics of the citadel, combined with archaeological excavations to determine citadel’s owner and date.