 The Song official Yu Yunwen was in command of the army defending the river . The Jurchen army was defeated while attacking Caishi between November 26 and 27 during the Battle of Caishi . The paddle @-@ wheel ships of the Song navy , armed with trebuchets that fired gunpowder bombs , overwhelmed the light ships of the Jin fleet . Jin ships were unable to compete because they were smaller and hastily constructed . The bombs launched by the Song contained mixtures of gunpowder , lime , scraps of iron , and a poison that was likely arsenic . Traditional Chinese accounts consider this the turning point of the war , characterizing it as a military upset that secured southern China from the northern invaders . The significance of the battle is said to have rivaled a similarly revered victory at the Battle of Fei River in the 4th century . Contemporaneous Song accounts claimed that the 18 @,@ 000 Song soldiers commanded by Yu Yunwen and tasked with defending Caishi were able to defeat the invading Jurchen army of 400 @,@ 000 soldiers . Modern historians are more skeptical and consider the Jurchen numbers an exaggeration . Song historians may have confused the number of Jurchen soldiers at the Battle of Caishi with the total number of soldiers under the command of Wanyan Liang . The conflict was not the one @-@ sided battle that traditional accounts imply , and the Song had numerous advantages over the Jin . The Song fleet was larger than the Jin 's , and the Jin were unable to use their greatest asset , cavalry , in a naval battle . 
 The Song official Yu Yunwen was in command of the army defending the river . The Jurchen army was defeated while attacking Caishi between November 26 and 27 during the Battle of Caishi . The paddle @-@ wheel ships of the Song navy , armed with trebuchets <a href='null_relcl' title='1'><mark>that</mark></a>fired gunpowder bombs , overwhelmed the light ships of the Jin fleet . Jin ships <a href='uninflect' title='2'><mark>were</mark></a> unable to compete because they <a href='uninflect' title='3'><mark>were</mark></a> smaller and hastily constructed . The bombs launched by the Song contained mixtures of gunpowder , lime , scraps of iron , and a poison <a href='null_relcl' title='4'><mark>that</mark></a>was likely arsenic . Traditional Chinese accounts consider this the turning point of the war , characterizing it as a military upset that secured southern China from the northern invaders . The significance of the battle is said to <a href='been_done' title='5'><mark>have</mark></a> rivaled a similarly revered victory at the Battle of Fei River in the 4th century . Contemporaneous Song accounts claimed that the 18 @,@ 000 Song soldiers commanded by Yu Yunwen and tasked with defending Caishi <a href='uninflect' title='6'><mark>were</mark></a> able to defeat the invading Jurchen army of 400 @,@ 000 soldiers . Modern historians <a href='drop_aux' title='7'><mark>are</mark></a>more skeptical and consider the Jurchen numbers an exaggeration . Song historians may <a href='been_done' title='8'><mark>have</mark></a> confused the number of Jurchen soldiers at the Battle of Caishi with the total number of soldiers under the command of Wanyan Liang . The conflict <a href='negative_concord' title='9'><mark>was</mark></a> <a href='negative_concord' title='10'><mark>not</mark></a>the one @-@ sided battle <a href='null_relcl' title='11'><mark>that</mark></a>traditional accounts imply , and the Song had numerous advantages over the Jin . The Song fleet was larger than the Jin <a href='null_genetive' title='12'><mark>'s</mark></a>, and the Jin <a href='uninflect' title='13'><mark>were</mark></a> unable to use their greatest asset , cavalry , in a naval battle . 
Da Song official Yu Yunwen was in command of the army defending tdariver . Thdaurchen army was defeated while attacking Caishi between November 26 and 27 during thedattle of Caishi . The dadle @-@ wheel ships of the Song navy , armed with trebuchets fired gunpowder bombs , overwhelmed the light ships of the Jdafleet . Jin ships was unable to compete because they was smaller and hastily constructed . The bombs launched by the Sodacontained mixtures of gunpowder , lime , scraps of iron , and a poison was likely arsenic . Traditional Chinese accounts consider dis the turnin point of the war , characterizing it as a military upset that secured southern China from the northern invaders . The significance of the batda is said to done rivaled a similarly revered victory at the Battdaof Fei River in the 4th century . Contemporaneous Song accounts claimed that the 18 @,da00 Song soldiers commanded by Yu Yunwen and tasked with defending Caishi was able to defeat the invading Jurchen army of 400 @,@ 000 soldiers . Modern historians more skeptical and consider the Jurchen numbers an exaggeration . Song historians may done confused the numberda Jurchen soldiers at the Battle of Caishi with the total number of soldiers under the command of Wanyan Liang . The conflict ain't the one @-@ sided battle traditional accounts imply , and the Song hadaumerous advantages ova the Jin . The Song fleet was larger than the Jin  , and the Jin was dable to use their greatest asset , cavalry , in a naval battle .