Wang Anshi, in his New Policies sponsored by Shenzong, has enhanced central authority over Song's frontier administrations, increased militia activity, increased troop levels and war horses sent to the frontiers (including the border areas with Dai Viet), and actively seeks loyal supporters in border regions who can heighten the pace of extraction of local resources for the state's disposal.

Officials at court debate the merits or faults of Wang's policies, yet criticism of his reforms even appears in Dai Viet, where the high officer Ly Thuong Kiet publicly announces that Wang's policies are deliberate efforts to seize and control their border frontiers.

Tensions between Song and Lý are at a critical point, and in these conditions any sign of hostility has the potential to ignite a war.

Wang Anshi tells the Song emperor that Dai Viet is being destroyed by Champa, with less than ten thousand soldiers surviving, hence it will be a good occasion to annex Dai Viet.

The Quang Nguyen chieftain Lưu Ky launches an unexpected attack against Yongzhou in 1075, which is repelled by the Song's Vietnamese officer Nung Trí Hoi in charge of Guihua.

Shenzong now seeks to cement an alliance with the "Five Clans" of northern Guangnan by issuing an edict which will standardize their once irregular tribute missions to visit Kaifeng every five years.

Shenzong has officials sent from the capital to supervise militiamen in naval training exercises.

Shenzong then orders that all merchants are to cease trade with the subjects of Dai Viet, a further indication of heightened hostility that prompts the Ly court under Ly Nhan Tông to prepare for war.

Upon hearing the news, the Ly ruler sends Ly Thuong Kiet and Nung Ton Dan with more than one hundred thousand troops to China to carry out a preemptive attack against the Song Dynasty troops.

In the autumn of 1075, Nung Tong Đan advances into Song territory in Guangxi while a naval fleet commanded by Ly Thuong Kiet captures Qinzhou and Lianzhou prefectures.

Ly Thuong Kiet calms the apprehensions of the local Chinese populace, claiming that he is simply apprehending a rebel who had taken refuge in China and that the local Song authorities had refused to cooperate in detaining him.