The Tayichiud (Cyrillic: Тайчууд, Taichuud) was one of the three core tribes of the Khamag Mongol confederation in Mongolia during the 12th century. They lived in the southern Zabaykalsky Krai and the Mongolian Dornod Province. Though the Khiyad Borjigids and the Tayichiuds were closely related and shared a common ancestor in Bodonchar, at times they were arch-rivals for the rule of the Khamag Mongol. Though Khabul Khan of the Borjigin had 7 sons, he had designated Ambaghai, a son of Sengum Bilge of the Tayichiud, as his successor. Thus Ambaghai Khan became the second khan of the Khamag Mongol. The rule of the Mongols had alternated between the Borjigid and the Tayichiud tribes, finally coming into the hands of Genghis Khan of Borjigid.