he served with Muqali and Jebe in a great raid in Shandong. Subutai played a key part in the campaign against the Tanguts of Xi Xia in 1226, serving as commander of the flank army to strike the Tanguts in the rear. While Genghis invaded the Xi Xia by a more traditional northern route, Subutai unexpectedly attacked from the west over the mountains and inhospitable deserts in modern Turkestan, causing Tangut resistance to collapse. The Tangut Empire was cut in two: with Genghis preventing reinforcements being sent west, Subutai subdued resistance in the west and joined with Genghis's main army to conquer the east. In 1227, he conquered the Jin districts along the upper Wei River, and even raided the Kingdom of Tibet. Though the Mongols conquered Xi Xia, Mongol operations against Jin China were interrupted by the death of Genghis Khan in 1227. Genghis Khan was succeeded by his son Ögedei in 1229. Conquest of Jin China (1231–1235) After a humiliating defeat by the resurgent Jin in 1230–1231, Ögedei personally led the main Mongol army against the Jin (in Central China) and appointed Subutai to salvage the situation. Subutai had originally been assigned to conquer the Kipchak Turks in central Russia in 1229, but was hurriedly recalled to China in 1229–1230 after the Mongol general Doqolqu suffered a major defeat. Against Subutai, the Jin generals retreated from Shaanxi and implemented a scorched earth policy to hold the fortified Tongguan Pass and block any access to the Jin stronghold of Henan. They calculated that the scorched earth policies would deny the Mongols the ability to sustain a lengthy siege, and their lines of fortifications and difficult terrain would prevent the Mongols from outmaneuvering them. At the Battle of Daohuigu, Subutai initially attempted to outflank the Jin by feinting an attack at the fortified location of Weizhou and maneuvering through an unguarded side corridor. Though the Jin were fooled by the feint, they moved with great alacrity once Subutai's main advance was discovered, and the attempt to break into the plains of Henan ended in failure after Subutai's advanced raiding parties were checked at Shan-ch’e-hui. The Mongols defeated a relieving force and captured Fengxiang, a secondary target, by concentrating 400 trebuchets at a corner of the wall. However, the overall campaign seemed to have reached a stalemate. In 1231–1232 Subutai made another attempt to outmaneuver the Jin fortified lines by using