Zhenzhu Khan (Inchü Qaghan, ) (died October 21, 645), personal name Inan (), full regal title Inchü Bilge Qaghan or in Chinese Zhenzhupiqie Khan (), was a khan of Xueyantuo, under whom Xueyantuo rose from being a vassal of Eastern Tujue to a mighty khanate ruling over northern and central Asia. During his reign, Xueyantuo largely aligned with the Tang dynasty, even though the two states were at odds at times, with the most serious dispute involving Tang's attempt to reestablish Eastern Tujue as a vassal state under the Qilibi Khan Ashina Simo—an attempt that eventually failed due to frequent incursions by Yi'nan's army against Ashina Simo. Throughout Yi'nan's reign, Xueyantuo remained powerful despite Tang attempts to curb its power, but after Yi'nan's death, a succession dispute between his sons, Bazhuo and Yemang (), led to Bazhuo's killing of Yemang and subsequent internal unrest. Further, Bazhuo attacked Tang, resulting in a major Tang retaliation campaign that, along with a revolt by the Huige, led to Xueyantuo's destruction in 646.
Prior to Tang's capture of Ashina Duobi
It is not known when Yi'nan was born, but it is known that he was the grandson of the Yiedie Khan Yishibo, who was the first ruler of the Xueyantuo, then a constituent tribe of the Chile confederation, which was then submitting to the rule of Eastern Tujue khans. It was said that at the time Yi'nan was initially Xueyantuo's ruler under Eastern Tujue's Jiali Khan Ashina Duobi, Yi'nan had 70,000 tents of people under him.
By 627, it was said that because of Ashina Duobi's misrule, several of the stronger members of the Chile, including Xueyantuo, Huige, and Bayegu (), rebelled. Ashina Duobi sent his son Ashina Yugu to attack the Chile rebels with some 400,000 horsemen, but were defeated by an army of only 5,000 horsemen commanded by the Huige chieftain Pusa (). At the same time, Xueyantuo also defeated four Eastern Tujue generals, and Ashina Duobi could not respond adequately. Ashina Duobi then sent the subordinate Tuli Khan Ashina Shibobi (), against the Chile, but the Huige and the Xueyantuo both defeated Ashina Shibobi, causing him to flee. (Ashina Duobi's subsequent anger at and brief detention of Ashina Shibobi eventually led to Ashina Shibobi also rebelling and entering into an alliance with Tang.)
By late 628, the northern vassals of Eastern Tujue had all rebelled, and they submitted to Yi'nan, offering him the title of khan. Yi'nan initially declined the title, not daring to use it. As Emperor Taizong of Tang wanted to enter into an alliance with Xueyantuo against Eastern Tujue, he sent the general Qiao Shiwang () as an envoy to Yi'nan, recognizing him the Zhenzhupiqie Khan (or Zhenzhu Khan in short), and awarding him with drums and banners. Yi'nan was very pleased, and he offered tribute to Emperor Taizong. It was said that by this point, his territory stretched from the Mohe to the east, Western Tujue to the west, and Gobi Desert to the south, and that many tribes, including Huige (回纥), Bayegu (拔也古), Adie (阿跌), Tongluo (同羅), Pugu (僕骨), and Baixi (白霫), all submitted to him. In fall 629, he sent his brother Tong () to offer tribute to Emperor Taizong, and Emperor Taizong, in return, awarded him with a sword and a whip, stating, "Lord, if your subordinates commit crimes, you can use the sword to execute those with major crimes, and whip those with minor crimes." Yi'nan was pleased, and this brought fear in Ashina Duobi, who requested a marriage with the Tang imperial clan, to no avail.
In 630, a Tang army commanded by the general Li Jing defeated the Eastern Tujue, capturing Ashina Duobi. Some of the Eastern Tujue people surrendered to Tang; some surrendered to Xueyantuo; and some fled to the west to Western Tujue or the nearby city states. Xueyantuo was now the predominant power to the north of the Tang empire.
Reign over former Eastern Tujue territory
As the supreme ruler over former Eastern Tujue territory, Yi'nan tried to maintain peaceful relationship with Tang by formally submitting to Tang, while at the same time strengthening his state.
In 632, Western Tujue's Siyehu Khan Ashina Dieli attacked Xueyantuo, and Xueyantuo forces defeated him, contributing to Ashina Dieli's subsequent downfall.