The Mongols under Chormaqan returned to Caucasus in 1232. Ganjak's walls were breached by catapult and battering ram in 1235. The Mongols eventually withdrew after the citizens of Irbil agreed to send a yearly tribute to the court of the khagan. Chormaqan waited until 1238, when the force of Möngke was also active to the north Caucasus. After subduing Armenia, Chormaqan tookTiflis. In 1238, the Mongols captured Lorhe whose ruler, Shahanshah, fled with his family before the Mongols arrived, leaving the rich city to its fate. After a putting up a spirited defense at Hohanaberd, the city's ruler, Hasan Jalal, submitted to the Mongols. Another column then advanced against Gaian, ruled by Prince Avak. The Mongol commander Tokhta ruled out a direct assault and had his men construct a wall around it and its prince Avak surrendered soon. By 1240, Chormaqan had completed the conquest ofTranscaucasia, forcing the Georgian nobles to surrender.
Invasion of Korea
In 1224 a Mongol envoy was killed in obscure circumstances and Korea stopped paying tribute. Ögedei dispatched Saritai (Sartaq) to subdue Korea and avenge the dead envoy in 1231. Thus, Mongol armies began to invade Korea in order to subdue the kingdom. The Goryeo King temporarily submitted and agreed to accept Mongol overseers. When they withdrew for the summer, however, Choe U moved the capital from Kaesong to Ganghwa Island. Saritai was hit with a stray arrow and died as he campaigned against them.
Ögedei announced plans for the conquest of the Koreans, the Southern Song, the Kipchaks and their European allies, all of whom killed Mongol envoys at the kurultai in Mongolia in 1234. Ögedei appointed Danqu commander of the Mongol army and made Bog Wong, the defected Korean general, governor of 40 cities with their subjects. When the court of Goryeo asked the peace treaty in 1238, Ögedei demanded the king to summon before him in person. The Goryeo king finally sent his relative Yeong Nong-gun Sung with 10 noble boys to Mongolia as hostages, temporarily ending the war in 1241It is said that Ögedei recruited his kheshig with Koreans