Meanwhile in the Tangut Kingdom, Huanzong’s cousin Li Anquan kills the emperor in a coup d'état with the empress and installs himself as Emperor Xiangzong.

Located south of the Gobi Desert and west of the Jin dynasty’s holdings, the Western Xia state is the weakest of China’s kingdoms.

It is thus a ripe target on which Genghis Khan can test the performance of his disciplined massed cavalry and, if successful, gain control of revenues from the East-West caravan routes.

The Western Xia army is also untrained and ill-equipped.

Regarding Western Xia as a roadblock to China, Genghis will repeatedly invade the state.

Genghis had led another raid into Western Xia in 1207, invading the Ordo region and sacking Wulahai, the main garrison along the Yellow River, before withdrawing in 1208.

Genghis now begins preparing for a full-scale invasion.

By invading Western Xia, he will gain a tribute-paying vassal, and also will take control of caravan routes along the Silk Road and provide the Mongols with valuable revenue.

Furthermore, from Western Xia, he can launch raids into the even more wealthy Jin dynasty.

Genghis in 1209 undertakes his campaign to actually conquer Western Xia.

Li Anquan requests aid from the Jin dynasty, but the new Prince Shao of Wei refuses to send aid.

After defeating a force led by Kao Liang-Hui outside Wulahai, Genghis captures the city and pushes up along the Yellow River, defeating several cities as he went, until he reached the fortress Kiemen which guarded the only pass through the Helan Mountains to the capital, Yinchuan.

Containing an army of up to seventy thousand plus fifty thousand reinforcements, the fortress proves too difficult to capture, and after a two-month standoff the Mongols feign a retreat, luring the garrison, led by Wei-ming Ling-kung, out onto the field where it is easily destroyed.

Genghis, his path now open, advances to the capital.

Yinchuan, well fortified, holds about one hundred and fifty thousand soldiers, nearly twice the size of the Mongol army.

This being the one of the Mongols’ first endeavors in siege warfare, they lack the proper equipment and experience to take the city.

They arrive at the city in May, but by October are still unsuccessful at breaking through.

Genghis attempts to flood the capital by diverting the river and its network of irrigation canals into the city.

The walls of Yinchuan are by January 1210 nearly breached.

However, the dike used to divert the river breaks, and the ensuing flood wipes out the Mongol camp, forcing the Mongols to take higher ground.

Despite this setback, the Mongols still pose a threat to Western Xia, and with the state's crops destroyed and no relief coming from the Jin, Li Anquan agrees to submit to Mongol rule, demonstrating his loyalty by giving a daughter, Chaka, in marriage to Genghis and paying a tribute of camels, falcons, and textiles.

Western Xia attacks the Jin dynasty later in the year, ending years of peace between the two countries, as punishment for their refusal to aid them against the Mongols.

Corruption has risen to new heights during Xiangzong's reign, and the peasants are mired in poverty.

The Western Xia army is also untrained and ill-equipped.

Xiangzong abdicates after his nephew Lǐ Zūnxū stages a coup d'état and seizes power as Emperor Shenzong; Xiangzong dies a month later in the same year, 1211.

Shenzong continues his predecessor's policy of invading the Jin Empire.