The problem with the Central Asian Khanates is that they survive mostly by the force of the ruler. That’s the reason why we see them collapsing such spectacularly, generally in a fratricidal war. Suluk is one such Khagan whose death created such a collapse that the Islam in Transoxania(Arab – Mawrannahar) spread only after he died. And yes, during the peak of the Arab Caliphate, no one, probably except the Chalukyas or Pratiharas had those many major victories under his belt with the Day of Thirst, the Battle of Defile and the Battle of Baggage occupying a place of pride and forced a retrogade march of the Arab armies.
After the defeat of Western Turkic Khaganate by Tang China in 658, the Turgesh broke away and declared independence, directly reporting to the Chinese. But, their independence didn’t stay long with the Western Turkish Khaganate ascertaining it’s authority. Called Suluk Chabish-chor by the Arabs and Su-Lu by the Chinese, Suluk was elected as the head of Turgesh Khaganate in 717 at the time when Westen Turkish Khaganate was embroiled in a civil war – due to the death of the king and due to the defeat of the Khaganate before the forces of Umayyad Caliphate.
It is possible that Suluk’s fight with the Arabs started when the Transoxanian kings solicited Chinese help against the Arabs in 719. A failed siege of Qasr al-Bahili, in response to the defeat and death of the Sogdian rebel leader Divashtich at Mount Mugh was followed by a general raid of the whole of Transoxania under Kul-chor. The Governor of Samarqand, Sa’id al-Khudhayna responded to this by sending a force under his son who based himself at Isthikhan. The Turgesh attacked but were beaten. In the battle which immediately followed, the Arabs were badly beaten and Sa’id had to be recalled. His successor, al-Kharashi brought back all Transoxania, except Ferghana Valley to control along with a general massacre.
Next major event is in 724. Muslim ibn Said is sent as the Governor to Khorasan with an aim to crush the Turks. The army, was raiding Ferghana Valley when it got an information that the Turgesh main force is advancing upon them under the Khagan Suluk. A hasty retreat with the Turgesh cavalry chasing them led to a confrontation near Khujand where they were trapped between the Turgesh and the their local supporters. Known popularly as the Day of Thirst, this cat and mouse chase for 11 days led to the near destruction of the Arab army and it’s Sogdian allies(the brother of the King of Samarkand is killed) led to the total collapse of Arab rule in that area. This resulted in Arabs trying to control the area, even to the extent of abolishing Jaziya which was rolled back in 728. The rollback resulted in a total rebellion and with the support of the Turgesh, Arabs were completely pushed out with Bukhara taken in the same year, leaving Arabs with only Samarqand, Kamarja and Dabusiya forts under their control. The Arabs retaliated by laying a siege of Bukhara in 729 under the then governor of Khurasan Ashras ibn Abdallah al-Sulami. The army, as usual, was harassed by the Turgesh all the way, till it was trapped near the oasis of Baykand without water. The king of Samarqand, Ghuruk switched sides at the opportune moment. With the Arab break out, the Turgesh, along with the remnants of the Persian Army under Khusrau, son of the Persian Crown Prince and a Chinese General Peroz, the moved towards Kamarja which fell after Arabs evacuated the fort while the Arabs laid siege to Bukhara. A relief army sent to Bukhara under Junayd ibn Abd al-Rahman al-Murri, was almost destroyed in the famous Battle of the Defile in 731 when they were attacked by Suluk. Junayd, reached Samarqand with a vastly depleted army but scored some victories against the Turgesh, finally leading to fall of Bukhara.
Though under formal Chinese suzerainty, Suluk tried to invade East but was badly defeated by the Chinese in Tarim Basin in 736.
A major Arab commander, al-Harith ibn Surayj, rose in revolt against Umayyad rule and took Balkh and Merv before defecting to the Turgesh three years later in 737, defeated. The Arabs responded by launching a campaign into Khuttal under Asad ibn Abdallah al-Qasri which supported al-Harith’s rebellion. A major Turgesh attack led by Suluk resulted in the capture of the complete baggage train. However, the army, a bit behind, withstood the attack. The loss of provisions forced the Arabs to turn back. Al-Harith joined the Turgesh at Tokharistan after the battle. This resulted in the end of Arab rule in Transoxania and the Khagan now entered Khurasan itself. Well, in spite all his successes, Suluk was unlucky finally.
In winter 737 Suluk, along with his allies al-Harith, Ghuruk and other allies entered Khurasan in force. However, a small contingent of 4000 under Suluk and al-Harith were forced into a battle at Kharistan unexpectedly. The Turgesh camp was destroyed completely and the king avoided capture because the Arabs failed to recognize him. A queen of the Khagan was killed by an eunuch who stabbed her to save her from capture and the Arabs recovered enormous spoils. The Umayyad high command itself was surprised at the victory. Though Suluk survived the battle, owing to the scale of the defeat, he was assassinated, under the instigation of Chinese for whom he is becoming too powerful, by Kul-chor who took power after him under the name Baga Khagan. This victory of Arabs led to the reversal of their fortunes and they captured the whole of Transoxania by 743. However, it would have been anybody’s guess if Suluk is not trapped or if Suluk is not assassinated. It is important to note that none of the major commanders were killed and the Turgesh armies were not destroyed in that fateful battle.