 Japan's defeat by World War II Allies created a power vacuum for Vietnamese nationalists of all parties to seize power in August 1945, forcing Emperor Bảo Đại to abdicate and ending the Nguyễn dynasty.Their initial success in staging uprisings and in seizing control of most of the country by September 1945 was partially undone, however, by the return of the French a few months later.According to a 2018 study in the "Journal of Conflict Resolution" covering Vietnam-China relations from 1365 to 1841, the relations could be characterized as a "hierarchic tributary system".