structural:expansion, information:highlighting
Consolidation of power (1206–1210)

From 1204 to 1209, Genghis Khan was predominantly focused on consolidating and maintaining his new nation. He faced a challenge from the shaman Kokechu, whose father Münglig had been allowed to marry Hö'elün after he defected to Temüjin. Kokechu, who had proclaimed Temüjin as Genghis Khan and taken the Tengrist title "Teb Tenggeri" (lit. "Wholly Heavenly") on account of his sorcery, was very influential among the Mongol commoners and sought to divide the imperial family. Genghis's brother Qasar was the first of Kokechu's targets—always distrusted by his brother, Qasar was humiliated and almost imprisoned on false charges before Hö'elün intervened by publicly reprimanding Genghis. Nevertheless, Kokechu's power steadily increased, and he publicly shamed Temüge, Genghis's youngest brother, when he attempted to intervene. Börte saw that Kokechu was a threat to Genghis's power and warned her husband, who still superstitiously revered the shaman but now recognised the political threat he posed. Genghis allowed Temüge to arrange Kokechu's death, and then usurped the shaman's position as the Mongols' highest spiritual authority.

During these years, the Mongols imposed their control on surrounding areas. Genghis dispatched Jochi northwards in 1207 to subjugate the Hoi-yin Irgen, a collection of tribes on the edge of the Siberian taiga. Having secured a marriage alliance with the Oirats and defeated the Yenisei Kyrgyz, he took control of the region's trade in grain and furs, as well as its gold mines. Mongol armies also rode westwards, defeating the Naiman-Merkit alliance on the River Irtysh in late 1208. Their khan was killed and Kuchlug fled into Central Asia. Led by Barchuk, the Uyghurs freed themselves from the suzerainty of the Qara Khitai and pledged themselves to Genghis in 1211 as the first sedentary society to submit to the Mongols.

The Mongols had started raiding the border settlements of the Tangut -led Western Xia kingdom in 1205, ostensibly in retaliation for allowing Senggum, Toghrul's son, refuge. More prosaic explanations include rejuvenating the depleted Mongol economy with an influx of fresh goods and livestock, or simply subjugating a semi-hostile state to protect the nascent Mongol nation. Most Xia troops were stationed along the southern and eastern borders of the kingdom to guard against attacks from the Song and Jin dynasties respectively, while its northern border relied only on the Gobi desert for protection. After a raid in 1207 sacked the Xia fortress of Wulahai, Genghis decided to personally lead a full-scale invasion in 1209.

Wulahai was captured again in May and the Mongols advanced on the capital Zhongxing (modern-day Yinchuan) but suffered a reverse against a Xia army. After a two-month stalemate, Genghis broke the deadlock with a feigned retreat; the Xia forces were deceived out of their defensive positions and overpowered. Although Zhongxing was now mostly undefended, the Mongols lacked any siege equipment better than crude battering rams and were unable to progress the siege. The Xia requested aid from the Jin, but Emperor Zhangzong rejected the plea. Genghis's attempt to redirect the Yellow River into the city with a dam initially worked, but the poorly-constructed earthworks broke—possibly breached by the Xia—in January 1210 and the Mongol camp was flooded, forcing them to retreat. A peace treaty was soon formalised: the Xia emperor Xiangzong submitted and handed over tribute, including his daughter Chaka, in exchange for the Mongol withdrawal.