Oghuz tribes occupied a vast territory in Kazakhstan along the Irgiz, Yaik, Emba, and Uil rivers, the Aral Sea area, the Syr Darya valley, the foothills of the Karatau Mountains in Tien-Shan, and the Chui River valley (see map).

The Oghuz political association developed in the 9th and 10th centuries in the basin of the middle and lower course of the Syr Darya and adjoining the modern western Kazakhstan steppes.

The beginning of the early Oghuz group formation is linked to the Western Zhetysu (often known, in Russian and other European languages, as Semirechye).

The Chinese sources, dated to the 7th and 8th centuries, located the 姑蘇 Gūsū (a Western Turkic tribe not belonging to the "Ten Arrows" Union[2][3][4]) consistently in the vicinity of Issyk Kul – Talas; Yury Zuev (1960) links these Gusu to the Oghuz Turks.

[5] The center of the Oghuz confederation shifted from the Issyk Kul area to the lower course of the Syr Darya under pressure of the refugees of the Sary Turgesh tribe.

[6] Zuev also notes two parallel passages: one from Venus' Secret Classic (Taibo Yinjing 太白陰經) which mentioned the 三屈 "Three Qu" (< MC *k(h)ɨut̚)[a],[7] and the other from al-Masʻudi's Meadows of Gold and Mines of Gems, which mentioned the three hordes of the Turkic Ġuz[8] Despite the similarity in name, Golden contends that the Toquz Oghuz (Chinese: 九姓 Jĭu Xìng "Nine Surnames"), from whom emerged the Uyghurs, were not the same people as the Oghuz who founded the Oghuz Yabgu state in Transoxiana.

The nomadic tribes of the Syr Darya Kangars were forced to join the Oghuzes, and a part of them migrated to the west to the northern Black Sea region.

Oghuz il extended from "Issyk Kul and Almalyk, in the south, to Sairam, in the west, to the city of Yangikent, which stands at the mouth of the river Syr (Syr-darya), and to the Kara-Kum (desert)".

[13] The capital of the Oghuz il was variously spelt Eni-Kent, Yangikent, Djanikand, Yenikent, Yanikand, all meaning New City, and also in Arabic literature al-Kariya al-Hadisa and in Persian literature Deh-i Hay; presently it is a Central Asian ghost town Jankent.

The Oghuz State played an important role in the military and political history of Eurasia.

In 985 the alliance with Kievan Rus defeated Volga Bulgaria, which increased the political power of the Oghuz State.

In 1041 Shahmalik Yabgu conquered Khorezm from the Ghaznavids, but two years later he was captured by the Seljuk forces and executed.

The movement was led by the head of the Kınık tribe Tughril and Chaghri Beg, the grandchildren of Seljuk.

[15] When the Oghuz drove the Pechenegs out of the Syr Darya delta a leader from the Barani clan took the title of yabghu.

Around 985 one of his commanders named Seljuk split off and moved to Jend south of the upper delta and converted to Islam.

The rulers were chosen by the codex of unwritten rules of customary law – "tore", from the most powerful clans.

The wives of the rulers bore the title "Khatun" and played a significant role in the court life.

The powerbase of the Oghuz State were semi-nomadic and nomadic tribes of Zhetysu and Siberia: Yughra, Charuk, Khalaj, Kimek, Karluk, Imur, Bayandur, Kai,[16] and the remaining tribes and sedentary population of the Kangar Union that submitted to the Oghuz Yabgu.

Later sources like Rashid-al-Din, Abu al-Ghazi Bahadur, and Selçukname omitted Charuklug from Kashgari's list, added Kizik, Karkin, and Yaparli, and divided the 24 tribes neatly into two 12-tribe group" Buzuks or Bazouk (Turkic and Turkmen: Bozoklar - Grey Arrows), and Uchuks (Turkic and Turkmen: Üçoklar - Three Arrows).

The discrepancy between the sources probably resulted from the Oghuz division into two exogamous parts, Buzuks and Uchuks belonging respectively to the right and the left wing of their army.