The Annamese had successfully evicted the Chinese…

The Annamese had successfully evicted the Chinese from their lands by 931, but a rebel army officer had murdered the Annamese leader shortly afterward.

The slain leader’s son-in-law, Ngo Quyen, has assembled a coalition of nobles and peasants to oppose the rebel, who seeks aid from China.

Ngo kills the rebel leader in 937, and in 938 awaits the Chinese forces at the Bach Dang River, where he orders iron spikes driven into the river bottom to a depth at which high tide conceals them.

The Chinese ships, sailing upstream, are impaled and trapped at the turn of the tide, enabling Ngo’s forces to decisively defeat the Chinese and end their control over Annam.