Battle of Caishi participant Southern Song dynasty
Song preparations for Caishi
Diplomatic exchanges between the Song and Jin did not stop during the period preceding the war. The History of Song claims that the Song realized that the Jin were planning for an invasion when they noticed the discourtesy of one of the Jin diplomats. Some Song officials foresaw the impending war, but Emperor Gaozong hoped to maintain peaceful relations with the Jin. His reluctance to antagonize the Jin delayed the fortification of the Song border defenses. The Song quickly built just three military garrisons in 1161. Wanyan Liang departed from Kaifeng on 1161 October 15. The offensive comprised four armies, and Wanyan Liang personally led the army that entered Anhui. The Jin passed the Huai River boundary on October 28, advancing into Song territory. The Song resistance was minimal because they had fortified the southern shore of the Yangzi River and not the Huai.Chen Kangbo (陈康伯), prime minister (宰相) of the Song dynasty, commanded the Song navy and designed the anti-Jin offensive strategy. Yu Yunwen, a civil official, commanded the defending Song army. The paddle-wheel warships of the Song fleet, equipped with trebuchets that launched incendiary bombs made of gunpowder and lime, decisively defeated the light ships of the Jin navy.