 <unk> the Song of violating the agreement and realizing the weakness of the Song , the Jin generals launched a second punitive campaign , again dividing their troops into two armies . Wanyan Zonghan , who had withdrawn from Taiyuan after the Kaifeng agreement and left a small force in charge of the siege , came back with his western army . <unk> , Taiyuan fell in September 1126 , after 260 days of siege . When the Song court received news of the fall of Taiyuan , the officials who had advocated defending the empire militarily fell from favor again and were replaced by <unk> who favored <unk> . In mid December the two Jurchen armies <unk> on Kaifeng for the second time that year . 
