 Planning to weaken the enemies first, the Đại Việt imperial family abandoned the capital and retreated south while enacting a scorched earth campaign by abandoning empty capital and cities, burning villages and crops where the Mongols occupied.At the same time, Sogetu moved his army up north in an attempt to envelop the imperial family in a pincer movement, but Kinh Nhân Tông managed to escape to Ninh Bình.Sogetu's army was weakened by the summer heat and the lack of food, so they stopped chasing the imperial family and move north to join with Toghan.