Yukuk Shad (r. 638–642, died 653) reigned in the final days of the Western Turkic Khaganate.
[3] His full title was 乙毗咄陆可汗 or Yipi Duolu Kehan (Zuev's reconstructed Old Turkic: *Yelbi Turuk Qaghan).
[4] He was the son of Illig Qaghan, ruler of the Eastern Turkic Khaganate and spent his early years there.
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.
[6] 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.
By 641, Yukuk consolidated most tribes between the Ili River and Siberia (including those not a part of Onok group) under his rule.
The rebels sought aid from Tang, and Emperor Taizong created El Kulug Shad's son as Irbis Sheguy khagan.
New khagan initially attacked Yukuk and forced him to escape to Isfijab (Sayram in modern Kazakhstan).