sentences:  Ngô Quyền calculated that the Southern Han would sail down the Bạch Đằng River to unload their troops right in the middle of Giao Châu to do the most damage.To prevent this incursion, Ngô Quyền strategized and ordered the waters of Bạch Đằng embedded with thousands of large wooden pikes hidden just beneath the rising tide water.He used boats with shallow drafts to instigate and lure the Southern Han toward the traps after the tide had risen.