Conquest of Kucha: The forces of Kucha surrender after a forty-day siege led by Tang dynasty general Ashina She'er, establishing Tang control over the northern Tarim Basin in Xinjiang.

The Tang campaign against Kucha was a military campaign led by the Tang dynasty general Ashina She'er against the Tarim Basin oasis state of Kucha in Xinjiang, which was aligned with the Western Turkic Khaganate. The campaign began in 648 and ended on 19 January 649, after the surrender of the Kuchan forces following a forty-day siege in Aksu. Kuchean soldiers tried to recapture the kingdom with the assistance of the Western Turkic Khaganate, but were defeated by the Tang army.

A siege is a military blockade of a city, or fortress, with the intent of conquering by attrition, or by well-prepared assault. Siege warfare is a form of constant, low-intensity conflict characterized by one party holding a strong, static, defensive position. Consequently, an opportunity for negotiation between combatants is common, as proximity and fluctuating advantage can encourage diplomacy.

The Tang dynasty, or the Tang Empire, was an imperial dynasty of China that ruled from 618 to 907, with an interregnum between 690 and 705. It was preceded by the Sui dynasty and followed by the Five Dynasties and Ten Kingdoms period. Historians generally regard the Tang as a high point in Chinese civilisation, and a golden age of cosmopolitan culture. Tang territory, acquired through the military campaigns of its early rulers, rivalled that of the Han dynasty.

The Tarim Basin is an endorheic basin in Xinjiang, Northwestern China occupying an area of about 888,000 km² (343,000 sq mi) and one of the largest basins in Northwest China. Located in China's Xinjiang region, it is sometimes used synonymously to refer to the southern half of the province, that is, Southern Xinjiang or Nanjiang, as opposed to the northern half of the province known as Dzungaria or Beijiang. Its northern boundary is the Tian Shan mountain range and its southern boundary is the Kunlun Mountains on the edge of the Tibetan Plateau. The Taklamakan Desert dominates much of the basin. The historical Uyghur name for the Tarim Basin is Altishahr, which means 'six cities' in Uyghur. The region was also called Little Bukhara or Little Bukharia. The basin is a major area for renewable energy development, particularly solar and wind power, with a focus on utilizing the vast Taklamakan Desert. A high-voltage power loop has been constructed around the basin, collecting energy from various sources and transmitting it to other regions.