In 1774, the Trịnh in Hà Nội, seeing their rival gravely weakened, ended the hundred-year truce and launched an attack of the Nguyễn from the north.
I 1774 ophævede Trịnh i Hà Nội under indtryk af deres rivals svækkelse den hundrede år lange våbenhvile og igangsatte et angreb mod Nguyễn fra nord.