Chinese forces under general Li Shiji besiege the strategic fortress city of Anshi (Liaoning) during the Goguryeo–Tang War.

Li Shiji, courtesy name Maogong, posthumously known as Duke Zhenwu of Ying, was a Chinese military general and politician who lived in the early Tang dynasty. His original family name was Xú, but he was later given the family name of the Tang imperial clan, Li, by Emperor Gaozu, the Tang dynasty's founding emperor. Later, during the reign of Emperor Gaozong, Li Shiji was known as Li Ji to avoid naming taboo because the personal name of Emperor Gaozong's predecessor, Emperor Taizong, had the same Chinese character "Shi". Li Shiji is also referred to as Xu Maogong and Xu Ji in the historical novels Shuo Tang and Sui Tang Yanyi.

Anshan is an inland prefecture-level city in central-southeast Liaoning province, People's Republic of China, about 92 kilometres (57 mi) south of the provincial capital Shenyang. As of the 2020 census, it was Liaoning's third most populous city with a population of 3,325,372 people, over an area of about 9,270 km² (3,580 sq mi) spanning 133 km (83 mi) from east to the west. Its built-up area encompassing the 4 Anshan urban districts, the 4 out of 5 urban Liaoyang districts and Liaoyang county largely being conurbated, was home to 2,712,789 inhabitants in 2020.

Liaoning is a coastal province in Northeastern China that is the smallest, southernmost, and most populous province in the region. With its capital at Shenyang, it is located on the northern shore of the Yellow Sea, and is the northernmost coastal province of the People's Republic of China.

The Goguryeo–Tang War occurred from 645 to 668 and was fought between Goguryeo and the Tang dynasty. During the course of the war, the two sides allied with various other states. Goguryeo successfully repulsed the invading Tang armies during the first Tang invasions of 645–648. After conquering Baekje in 660, Tang and Silla armies invaded Goguryeo from the north and south in 661, but were forced to withdraw in 662. In 666, Yŏn Kaesomun died and Goguryeo became plagued by violent dissension, numerous defections, and widespread demoralization. The Tang–Silla alliance mounted a fresh invasion in the following year, aided by the defector Yŏn Namsaeng. In late 668, exhausted from numerous military attacks and suffering from internal political chaos, Goguryeo and the remnants of Baekje army succumbed to the numerically superior armies of the Tang dynasty and Silla.