|Date of death||653 Kunduz, Kunduz District, Kunduz Province, Afghanistan|
Yukuk Shad (r. 638–642, died 653) (or Illig Beg Tughluq or Chinese: 欲谷設/欲谷设) reigned in the final days of the Western Turkic Khaganate. His name Yukuk means Snow Leopard (Panthera Uncia) and title Shad means prince.
He was a member of Ashina royal clan of the Turkic khanate. He was the son of Illig Qaghan, ruler of the Eastern Turkic Khaganate and spent his early years there. In 627, he was assigned to suppress a rebellion around Tien shan but was defeated. Three years later, his father was also defeated and the Eastern Turkic Khaganate dissolved.
Invitation from the West
After the death of Tong of the Western Turkic Khanate in 628 (?), the central authority of the khagans among the West Turks was challenged by the leaders of the ten tribes collectively known as Onok. However there was also a competition between the two wings of Onok; i.e., the Dulu and the Nushibi . Ishbara Tolis who became the khagan in 634 tried to increase his authority by the support of Nushibi. But his camp was raided and he had to escape to Fergana (in modern Uzbekistan). But even after his escape, the leaders of the ten tribes preferred a khagan from the Ashina house to maintain the delicate balance between the two wings. Yukuk’s name was proposed by a certain Tun Tudun. Yukuk whose father’s territory had long been lost readily accepted the invitation. But it soon turned out that although he was welcome by Tulo, Nushibi tribes opposed him.
Yukuk as a khagan
According to one source he defeated a rival called Illig Beg Ishbara Yaghbu Khagan (Ashini Bobo) (ruled 639–641) and sent governors to the Tarim Basin, Tashkent, Samarkand and Bactria.
After a civil war between the two wings of the Onok, Ili River became the border line between the Nushibi (the south of the river) and the Tulo (north of the river ) by the Ili river treaty in 638. Yukuk assumed the title Ilig Beg Tughluk Khagan and became the khagan of the north side. By 641, Yukuk consolidated most tribes between the Ili River and Siberia (including those not a part of Onok group) under his rule. In 642 he raided Samarkand (in modern Uzbekistan) one of the wealthiest cities of the silk road. But the distribution of loot between the tribes caused problems, and he lost the support of Tulo tribes. Nushibi tribes, supported by Tang China, saw this as a chance to overthrow Yukuk. They elected Irbis Seguy (Ilig Beg Shekuei Qaghan) as they khagan. This election meant the end of Onok union. Initially they attacked Yukuk and forced him to escape to Isfijab (Sayram in modern Kazakhstan). They further laid a siege on Istijab . But although Yukuk got no help from Tulo tribes he managed to defeat them. After this victory, Yukuk tried to regain Tulo support. But Tulo leaders rejected his proposal. Yukuk, feeling insecure without tribal support, escaped to Kunduz (in modern Afghanistan) in 642
Yukuk spent the rest of his life in Kunduz and died in 653. His heir was Inan (Jenchu). Inan was one of the last representatives of the family. But his authority was limited to a single city.