 Song armies led by general Bi Zaiyu ( 畢再遇 ; d . 1217 ) captured the barely defended border city of Sizhou 泗州 ( on the north bank of the Huai River across from modern Xuyi County ) but suffered large losses against the Jurchens in Hebei . The Jin repelled the Song and moved south to besiege the Song town of Chuzhou 楚州 on the Grand Canal just south of the Huai River . Bi defended the town , and the Jurchens withdrew from the siege after three months . By the fall of 1206 , however , the Jurchens had captured multiple towns and military bases . The Jin initiated an offensive against Song prefectures in the central front of the war , capturing Zaoyang and Guanghua ( 光化 ; on the Han River near modern Laohekou ) . By the fall of 1206 , the Song offensive had already failed disastrously . Soldier morale sank as weather conditions worsened , supplies ran out , and hunger spread , forcing many to desert . The massive defections of Han Chinese in northern China that the Song had expected never materialized . 
