This paper analyzes the battle situation of the Goguryeo-Táng War in 661. In 661, 350,000 Táng troops attacked Liaodong, Yalu River, and Pyongyang. Goguryeo's defense strategies were to block the supply routes of the Yalu River while guarding the castle with a Liaodong defense net, press the party in connection with nomadic forces in the northwest, wait for the party's lack of food, and turning into an offensive phase.
On the Liaodong front, Chéngmíngzhèn's army(Nubang attacking army) fought against Go Eul-deok's army outside and captured Go Eul-deok, but Goguryeo's army succeeded in protecting the divinity and stopping the party's advance. On the Yalu River front, Qì bì hé lì's army(Liáodōng attacking army) tried to secure a supply base north of the Yalu River, but was previously blocked by tens of thousands of Namsaeng's army troops deployed south of the Yalu River. However, when the Yalu River suddenly froze, Qì bì hé lì's army crossed the Yalu River, defeated Namsaeng's army, and chased Cheolsan. On the Pyongyang front, party naval forces led by Sūdìngfāng(Pyongyang attacking army), Rèn yǎ xiāng(Paegang attacking army), and Páng xiàotài(Okjeo attacking army) defeated Goguryeo naval forces at the mouth of the Pae River and succeeded in siege Pyongyang. However, while Sūdìngfāng's army in charge of Pyongyang supplies were blocked by Namsaeng's army, the supplies were cut off and failed to maintain the momentum and struggled with Goguryeo's resistance. In addition, the Silla army, which was advancing to Goguryeo, was unable to advance to Goguryeo due to the Baekje Revival Army. Sūdìngfāng asked Silla to supply it to overcome these difficulties.
In this situation, Qìdān, which was linked to the nomadic forces of the meadow, Töles and Goguryeo, rebelled against the party. As a result, the Ā shǐ nà zhōng and Xiāosìyè forces that attacked the fluctuation and the Qì bì hé lì forces that attacked the Yalu River retreated toward Töles, making the party more disadvantageous. When the Táng army began to withdraw to the Töles front, the Liaodong Goguryeo army switched to an offensive and launched a counterattack, and in the process, Chéngmíngzhèn, who remained in Liaodong, lost. In Pyongyang, Goguryeo's counterattack intensified, and it achieved certain results in stealing two military bases of the party and sending envoys to Japan to break through the party's siege. On the other hand, the party faced the worst situation of having to wait for the supply of Silla while defending Goguryeo's counterattack in cold weather.