Four Garrisons of Anxi

The Four Garrisons of Anxi were Chinese military garrisons installed by the Tang Dynasty between 648 and 658. They were stationed at the city and capital of the Indo-European statelet Kucha, Khotan, Kashgar and Karashahr. The capital of Kucha was also the seat of the Protectorate General to Pacify the West. The troops were sent and stationed here from within Tang China proper.

The fortress of the Four Garrisons were first built in 648, when the main opponent statelets in the Tarim Basin were subdued by force. Shortly after, in 651, the garrisons were taken by the Turkic prince Ashina Helu, until the conquest of Su Dingfang after 657.

The main challengers for the Chinese establishing their hegemony over the region were the Tibetans, who since 662 had constantly set their aggression over the region and briefly seized it between 670 and 692. During this period the Chinese re-captured them in 675, 679, 682 and again in 686. Meanwhile in 679, another fortress was built in Suyab, situated near the Chui River, this would later replace Karashahr as one of the Four Garrisons until 719, when the Turgesh took over it.

In 692, with the last defeat of Tibetans, and after a brief seizure of Kucha by Turgesh for 8 months in 709, the Four Garrisons were continuously controlled by the Chinese, until their eventual loss. Even though most of the regular prefectures at Hexi Corridor, such as Liangzhou (764), Ganzhou, Suzhou (766), Guazhou (776), Yizhou (781) and Shazhou (787) were occupied between the 760s and 780s by the Tibetans, and the contacts between the capital were limited, the Chinese continued to maintain the order of these garrisons until 791, when these, along with the seat of Protectorate General to Pacify the West, would eventually fallen to the Tibetan hands.