The Song have by 1077 destroyed two other Vietnamese armies and marched towards their capital at Thang Long (modern Hanoi).

Song forces halt at the Nhu Nguyet River (in modern Bac Ninh Province), where Ly Thurong Kiet has defensive ramparts built on the southern banks.

However, Song forces break through his defense line and their cavalry advances to within several kilometers of the capital city.

The Vietnamese counterattack and push Song forces back across the river while their coastal defenses distract the Song navy.

Ly Thurong Kiet also launches an offensive, but loses two Ly princes in the fighting at Kháo Túc River.

According to Chinese sources, "tropical climate and rampant disease" severely weaken Song's military forces while the Ly court fears the result of a prolonged war so close to the capital.