structural:reformatting, linguistic:voice_change, quality:correction
Middle Kaiyuan era

In 723, Zhang Jiazhen was demoted on account of a corruption scandal involving his brother Zhang Jiayou (張嘉祐). His position was filled by Wang Jun, who was soon himself demoted over suspicions, never proven, that he was plotting treason. With Zhang Yue thus effectively being the senior chancellor, Zhang Yue promoted literary studies, which Emperor Xuanzong also favored. In 724, he also commissioned the chief imperial astronomer Nangong Shuo (南宮說) to carry out a major astronomical survey to observe the sun and the North Star at various points of the empire.

Also in 724, it was discovered that Wang Shouyi had engaged sorcerers to make amulets for Empress Wang to wear, hoping that the use of magic would allow her to have a son. Empress Wang was deposed and reduced to commoner rank, while Wang Shouyi was exiled and subsequently ordered to commit suicide in exile. Empress Wang died later in the year, and it was said that the eunuchs and the ladies in waiting mourned her bitterly and Emperor Xuanzong much regretted his treatment of her. Still, after Empress Wang's removal and death, Consort Wu became undisputed mistress of the palace and was treated inside the palace like an empress would be. Still, in 726, when Emperor Xuanzong considered creating her empress, he encountered oppositions from officials on two grounds – that her Wu clan was hated by the people and that as she had her own sons, the position of Li Siqian the Crown Prince (whose name had been changed to Li Hong by this point) would be threatened. As a result, Emperor Xuanzong never created her empress. But Consort Wu's was a chief favorite of the emperor and undisputed mistress of the palace until her death and had political power.

In winter 725, Emperor Xuanzong, at Zhang Yue's urging, carried out a magnificent ceremony at Mount Tai to offer sacrifices to heaven and earth.

On 11 May 726, Zhang Yue was accused of corruption by several officials that he had blocked the advances of – Cui Yinfu (崔隱甫), Yuwen Rong, and Li Linfu – and was found to have committed corruption. At the intercession of Gao Lishi, however, Zhang Yue was removed only from his chancellor post on 18 May and permitted to maintain his title and a number of other posts. He was replaced by Li Yuanhong on 15 May, and subsequently, Du Xian was also added as a chancellor.

In 727, at the suggestion of the general Wang Junchuo (王君㚟), Emperor Xuanzong commissioned Wang Junchuo to attack the Tibetan Empire, and after a Tibetan incursion in late 726, Wang counterattacked and inflicted losses on Tibetan forces commanded by the general Xinuoluogonglu (悉諾邏恭祿). Later in the year, though, Xinuoluogonglu and another general, Zhulongmangbuzhi (燭龍莽布支) attacked and captured Wang's home prefecture Gua Prefecture (瓜州, roughly modern Jiuquan, Gansu), taking Wang's father Wang Shou (王壽) captive. As a result, Wang Junchuo did not dare to counterattack, and subsequently blamed the defeat on a number of tribal chiefs in the area and had them exiles. In response, Yaoluoge Hushu (藥羅葛護輸), the nephew of one of the chiefs so exiled, Yaoluoge Chengzong (藥羅葛承宗), ambushed Wang Junchuo and killed him, and while Yaoluoge Hushu was forced to flee thereafter, for several years Tang did not engage in any offensive campaigns in the region.

Around the same time, Emperor Xuanzong began to build a residential complex in the palace for imperial clan members, known as the Mansion of the Ten Princes (十王院), to centralize their residence. Thereafter, imperial princes, including the crown prince, would rarely live outside the palace complex.

On 6 December 728, Emperor Xuanzong added the general Xiao Song as a chancellor. Subsequently, in 729, with Yuan, even though he was senior chancellor, unable to curb the disputes between Li Yuanhong and Du, Emperor Xuanzong removed all three from chancellor positions, promoting Yuwen and Pei Guangting to be chancellors in their stead – in Yuwen's case, for his abilities to find ways to add to the imperial treasury by imposing special taxes and levies. Later in the year, though, Yuwen made false accusations against the general Li Hui (李褘) the Prince of Xin'an (Emperor Xuanzong's second cousin) and was exiled, and subsequently died in exile. Still, it was said that it was starting from Yuwen's times that Emperor Xuanzong began to pay attention on taxes to replenish the imperial treasury, which traditional historians viewed as the start of his inflicting financial burdens on the people. Further, with Pei in charge of the civil service system, it was said that due to Pei's strict adherence to seniority, the Tang civil service system began to lose its ability to find talented people to serve in offices.

In 730, the Khitan general Ketugan (可突干) killed the king Li Shaogu (李邵固) and took over the reign of the Khitan and the Xi personally, forcing the king of the Xi, Li Lusu (李魯蘇) to flee to Tang for protection. Tang sent an army to attack the Khitan, but meanwhile made peace with the Tibetan Empire. Initially, the campaign against the Khitan did not succeed, but in 732, with Li Hui in command, Tang forces dealt Ketugan a serious defeat and causing many of Ketugan's subordinates to defect and submit to Tang, although Ketugan was not captured.