A jüz (Kazakh: жүз) is one of the three main territorial divisions in the Kypchak Plain area that covers much of the contemporary Kazakhstan. Variably, a jüz is believed to be a confederation or alliance of Kazakh nomads. Kazakh legends tell that ancestry of the three main Kazakh jüzes derived from three brothers.
Contemporary Kazakh clans 
The meaning and origins of the jüz formations have been subject to different interpretations. Some researchers argued that originally jüz corresponded to tribal, military alliances of steppe nomads that emerged around mid-16th century after the disintegration of the Kazakh Khanate. Others proposed that jüz are geographical ecological zones separated by natural boundaries. Nomads adopted to these geographical zones and developed nomadic migration routes within the natural boundaries. According to Kazakh legends, the three jüzes originated from the children and grandchildren of the three sons of the mythical forefather of Kazakhs. Another version of the legend asserts that the three jüzes were the territorial inheritances of the three sons of the mythical founder father. In Kazakh language, "jüz" means "hundred" or "face"; in Arabic, "jüz" refers to "section", "division".
Historically, the Great jüz (Kazakh: Ұлы жүз, Ulı jüz; Russian: Старший жуз, Starshiy zhuz) or Senior Century nomads inhabited the northern lands of the former Chagatai Ulus of the Mongol Empire, in the Ili River and Chu River basins, in today's South-Eastern Kazakhstan and China's Ili Kazakh Autonomous Prefecture (northern Xinjiang). It was also called Uysun jüz. The Great jüz representatives were known for their skills in governing and uniting all other nomadic tribes into one country. Kazakhstan's ruling elite, including current president Nursultan Nazarbayev, former First Secretary of the Communist Party of Kazakhstan Dinmukhamed Konayev, as well as famous poet Jambyl Jabayev are representatives of the Great juz.
The Middle jüz (Kazakh: Орта жүз, Orta jüz; Russian: Средний жуз, Sredniy zhuz) or Middle Century nomads nomadized in the eastern lands of the former Jochi's Ulus, in Central, Northern and Eastern Kazakhstan. It was also known as Argyn jüz. Kazakhstan's famous poets and intellectuals, including Abay Qunanbayuli, Akhmet Baytursinuli, Shokan Walikhanuli and Alikhan Bokeikhanov were born in the Middle jüz territories.
The Junior jüz (Kazakh: Кiшi жүз, Kişi jüz; Russian: Младший жуз, Mladshiy zhuz) or Junior Century nomads occupied the lands of the former Nogai Khanate in Western Kazakhstan. It was also called Alshyn jüz. They were known for their fierce warriors.
Each jüz contains a number of clans, which share a presumed genealogy of forefathers going back to the presumed ancestor. Each clan is divided into smaller groups down to the smallest lineage. As Kazakhs practice exogamy, each individual is expected to know his ancestors up to the seventh forefather ("Byr Ata"). Marriage within Byr Ata was considered to be incest taboo.
Great jüz 
There have been several attempts to determine the exact names and nature of top level clans throughout the 19th and early 20th centuries. However, different studies created vastly different names and population numbers for the steppe clans. Although disputed, generally accepted names of the first order Great jüz or Uisun clans are:
- Jalair 100-110,000
- Alban 100,000
- Dulat 250,000
- Sary-Uisyn 10,000
- Sergeli 40,000
- Shaprashty 50-60,000
- Suan 30,000
- Oshaqty 20,000
- Ysty 40-45,000
- Qangly and Shanyshqyly 50,000
Middle jüz 
- Argyn 500,000
- Kerei 100-110,000
- Naiman 600,000
- Qonyrat 40-45,000 in Kazakhstan, and more than 100,000 in Central Asia
- Qypchak 140-150,000
- Taraqty 10,000
- Waq 55-60,000
Junior jüz 
The Junior jüz consisted of three groups:
- Baiuly: 540-550,000
- Alimuly: 270-315,000+
- Jetyru: 265-275,000
See also 
- Қазақтар (этногенез) (Kazakhs (ethnogenesis)) in Kazakh Wikipedia.
- List of medieval Mongolian tribes and clans
- Orda (structure)
- Mukanov M.S., "Ethnic territory of Kazakhs in 18 - beginning of 20th century", Almaty, 1991, Муканов М. С. "Этническая территория казахов в 18 – нач. 20 вв. Алма-Ата, 1991 (Russian)
- Svat Soucek, "A History of Inner Asia". Cambridge University Press (2000). ISBN 0-521-65704-0.
- Genealogy of the Kazakhs (Kazakh) (Russian)