Dau Go Cave (the Cave of Wooden Stakes) is 7km or 30 minutes boat trip from the shore. Dau Go Cave is believed to have been the place where General Tran Hung Dao hid weapons in the war against the invaders in the 13th century A.D. Dau Go Cave is one of the biggest caves of Halong Bay. The cave offers stunning stalactites and stalagmites. The cave of Dau Go has 3 sections started being inhabited from the 3rd century A.D. In the last war against the Mongol invasion, General Tran Hung Dao used the cave as a timber store.
The timbers were logged from Bai Chay Town (Ha Long City) and were brought into the cave where they were whittled into pointed stakes and tipped with steel. The stakes were then carried to Bach Dang River mouth where they were driven into the river bed. At high tide, the whole area of trap was hidden and at low tide they would emerge from under water. When the trap was hidden at high tide, the Vietnamese used light boats with royal flags to lure the Mongol fleet into the trap area, at low tide, they attacked at the invaders from both sides of the river with fire and arrow bow. The whole fleet of over 40 000 troops were sunken to the river and killed in 1288 and Vietnam remained independent after 3 times being attacked and destroyed. A complete tour of Dau Go Cave may take up to 1 hour or 1 and a half hour. The trip can be combined with a visit to the Thien Cung Cave (The Heavenly Palace Cave).