The Battle of Ikh Bayan (; literally in Mongolian: Battle of Great Rich), was a major expedition launched against the Xiongnu by the Han Dynasty in June, 89. The battle was a success for the Han under Dou Xian (d. 92). Dou Xian brought the main body of his troops in triumphal progress north to the Khangai Mountains, west of present day Kharkhorin. There he erected the Stele of Yanran, composed by his client, the historian Ban Gu, which celebrated the achievement of the battle.