The Khalkha (, Mongolian script: , ) have been the largest subgroup of Mongol people in modern Mongolia since the 15th century. The Khalkha, together with Chahars, Ordos and Tumed, were directly ruled by Borjigin khans until the 20th century; unlike the Oirats, who were ruled by Dzungar nobles or the Khorchins, who were ruled by Qasar's descendants. The two original major Khalkha groups were ruled by the direct male line descendants of Dayan Khan. The Baarin, Khongirad, Jaruud, Bayaud and the O'zeed (Ujeed) became Dayan Khan's fifth son Achibolod's subjects, thus formed the Southern Five Halhs. Seven northern Khalkha otogs: 1) Jalairs, Olkhonud; 2) Besut, Iljigin; 3) Gorlos, Keregut; 4) Khuree, Khoroo, Tsookhor; 5) Khukhuid, Khatagin; 6) Tanghut, Sartuul; 7) Uriankhai became Dayan Khan's youngest (could be third) son Geresenje's () subjects. Khotogoids are close in culture and language to the Khalkha Mongols. There were also numerous direct descendants of Genghis Khan who had formed the ruling class of the Khalkha Mongols prior to the 20th century, but they were and still also regarded as Khalkha Mongols rather than belonging to a special unit. The Thirteen Khalkhas of the Far North are the major subethnic group of the independent state of Mongolia. They number 1,610,400 (78.8%) of Mongolia's population (1989 figures). The Khalkha or Halh dialect is the standard written language of Mongolia. Etymology The term Халх ("Halh, Khalkha") has always puzzled linguists and historians. One possible interpretation is that it shares the same root as the words xалхавч "shield" and халхлах "to protect; to cover; to shield; to hide; to intercept", although there is no noun or verb xалх that independently exists besides the ethnic group's name. In a similar manner, the sub-ethnic groups within the Khalkha Unit have been historically recorded in books, journals, and documents as "Jalair Khalkha", "Sartuul Khalkha", "Tanghut Khalkha" etc. Even the word order in the phrases Southern Five Khalkha and Northern Thirteen Khalkha implies that the word Халх correlates to the units within the Southern and Northern tribal federations, but it does not stand for the group as a whole. Lastly, Mongolians have always linked the term Халх to the name of the Khalkhyn Gol. History Dayan Khan created the Khalkha Tumen out of Mongols residing in the territory of present-day central Mongolia and northern part of Inner Mongolia. In Mongolian historical sources such as Erdeniin Erih ("The Beads of Jewel") it