Tang campaign against Kucha

The Tang campaign against Kucha, known as Qiuci in Chinese sources, was a military campaign led by the Tang Dynasty general Ashina She'er against the Tarim Basin oasis state of Kucha in Xinjiang. The campaign began in 648 and ended in 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.

The Tang court established a military garrison in Kucha, and placed the oasis state under the governance of the Anxi Protectorate. Hostilities between the Western Turkic Khaganate and the Tang Dynasty continued after the fall of Kucha. The Tang would later annex the khaganate after a military expedition in 657.

Background
Kucha, a kingdom in the Tarim Basin, was a vassal of the Western Turkic Khaganate. The oasis state was ruled by the Sufa royal family. Under the reign of Emperor Gaozu, the king Sufa Bushi provided the Tang court with tribute in 618. In 630, Bushi's successor Sufa Tie submitted to the Tang as a vassal. A Buddhist of the Hinayana sect, Tie had hosted the Buddhist monk Xuanzang when he arrived in Kucha during the same year.

Kucha supported Karasahr when the oasis state ended its tributary relationship with the Tang court in 644. The king of Kucha, Sufa Tie, renounced Tang suzerainty and allied with the Western Turks. Emperor Taizong responded by dispatching a military campaign led by the general Guo Xiaoke against Karasahr.

Karasahr was besieged in 644 by Guo. Tang forces defeated the kingdom, captured the king, and a Tang loyalist was enthroned as ruler. The new king was deposed by his cousin, and the Tang once again intervened by sending a military expedition led by Ashina She'er in 648. After Karasahr fell, Ashina's army began its march towards Kucha.

Ashina She'er was a member of the Khaganate's ruling Ashina royal family. He joined the Tang forces after his surrender in 635, and served as a general leading a campaign against Karakhoja. His familiarity with the region as a former Turkic ruler contributed to his success commanding the campaigns against Kucha and Karasahr. Prior to his recruitment as a Tang general, he reigned for five years between 630 and 635, governing the cities of Beshbaliq and Karakhoja.

Campaign


Ashina She'er led his army to Kucha after the fall of Karasahr. Tie had died in 646, and his brother Heli Bushibi inherited the throne as Kucha's king. Informed of the upcoming invasion, Bushibi tried to appease the Tang court by promising the kingdom's submission in 647. The belated request did not work, and the attack commenced as planned.

Ashina's soldiers were organized in five columns. The general eliminated sources of future reinforcements for Kucha by attacking Turkic tribes that had allied with the oasis state. He defeated Chuyue near Guzheng and the Chumi tribes inhabiting the Manas River.

The forces defending Kucha, consisting of 50,000 soldiers, were lured and ambushed by Ashina. They chased after a group of 1,000 horsemen employed by Ashina as a decoy, but encountered additional Tang forces that mounted a surprise attack. The Kuchean forces were defeated and retreated to Aksu, a nearby kingdom in the Tarim Basin. Ashina captured the king following a forty-day siege, ending with the surrender of the Kucha forces on 19 January 649. One of Ashina's officers, acting as a diplomat, persuaded the chieftains of the region to surrender instead of fighting back.

Guo Xiaoke, who had led the first Tang campaign against Karasahr in 644, was installed in the kingdom as protectorate-general of the Anxi Protectorate, or Protectorate to Pacify the West. While Ashina was in pursuit of the Kuchean king, Nali, a Kuchean lord, traveled to request the help of the Western Turks. Guo was assassinated after the Kuchean soldiers retook the kingdom with the military assistance of the Western Turks. Ashina returned to Kucha, captured five of the kingdom's cities, and forced the remaining cities to surrender. Tang control was re-established in the oasis state. The brother of the former king, a yabgu or viceroy, was enthroned by the Chinese as a subject of the Tang empire.

The king of Kucha was taken to the Tang capital as a prisoner. Execution was the punishment of rebellion in accordance with Tang law. The king was pardoned by Taizong and released after a ritual venerating the emperor's ancestors. He was also named Great Army Commander for the Militant Guards of the Left, a title he received from the emperor.

Aftermath
In retribution for the death of Guo Xiaoke, Ashina She'er ordered the execution of eleven thousand Kuchean inhabitants by decapitation. It was recorded that "he destroyed five great towns and with them many myriads of men and women... the lands of the west were seized with terror." After Kucha's defeat, Ashina dispatched a small force of light cavalry led by the lieutenant Sie Wanpei to Khotan, ruled by the king Fu Shouxin. The threat of an invasion persuaded the king to visit the Tang court in person.

The conquest of Kucha established Tang rule over the northern Tarim Basin in Xinjiang. The region was governed under the same structure as the main prefectures of Tang China. Tang armies had annexed Karasahr and Karakhoja previously, while Kashgar, Khotan, and Yarkand had surrendered to the Tang voluntarily. Kucha became the center of the Anxi Protectorate in 649, created in 640 to administer the parts of Xinjiang controlled by the Tang Dynasty. A Tang military garrison was installed in the oasis state as one of the Four Garrisons of Anxi, along with the garrisons in Kashgar, Khotan, and Karasahr.

The fall of Kucha led to the decline of an Indo-European Tarim Basin. While Chinese rule had an impact on the culture of the region in the form of art and politics, the most significant change was the rising influence of Turkic language and culture. The composition of Tang armies in Central Asia contributed to this change. The majority of the Tang soldiers and generals stationed in the Tarim Basin by the Chinese were of Turkic ancestry.

The Tang Dynasty continued their war against the Western Turks under the reign of Emperor Gaozong, Taizong's successor. Gaozong conducted a campaign led by general Su Dingfang against the Western Turk qaghan, Ashina Helu in 657. The qaghan surrendered, the Western Turks were defeated, and the khaganate's former territories were annexed by the Tang. The Tang retreated from beyond the Pamir Mountains in modern Tajikistan and Afghanistan after a Turkic revolt in 662, but retained a military presence in Xinjiang. The Tang, Tibetans, and Turks competed for influence in the Tarim Basin for the remainder of the dynasty. The Tang Dynasty ended in 907 with the abdication of Emperor Ai.