The Trịnh–Nguyễn War lasted from 1627 until eventually 1672. The Trịnh Military staged at least 7 offensives, all of which did not seize Phú Xuân. For the time, beginning in 1651, the Nguyễn them selves went on the offensive and attacked parts of Trịnh territory.The Trần dynasty also adopted a singular approach to train new emperors