白藤江
The Bạch Đằng River ran through Yen Hung district (in Quảng Ninh province) and Thuy Nguyen (in Hai Phong) before reaching the sea. This was where the earlier well-known battle of Ngô Quyền against the Southern Han had taken place in 938. Beginning from March, Trần Hưng Đạo began preparing the battlefield. He used the same tactic that Ngô Quyền had against the Chinese in 938. He studied the tidal lore, and ordered beds of stakes to be planted under the water and arranged ambushes in a unified plan of campaign.