[1] – December 31, 669[2]), courtesy name Maogong, posthumously known as Duke Zhenwu of Ying, was a Chinese military general and politician who lived in the early Tang dynasty.

Zhai agreed, and after the victory over Zhang, the rebels approached the eastern capital Luoyang and declared Li Mi their leader, with the title of Duke of Wei.

As a result, more than 200,000 men joined Li Mi within about 10 days, and a number of commanderies submitted to him, including the major rebel generals Dou Jiande and Zhu Can.

In spring 618, Emperor Yang was killed at Jiangdu (in modern Yangzhou, Jiangsu) in a coup led by the general Yuwen Huaji.

The enemies made peace, with Li Mi nominally submitting to Yang Tong, as both sides prepared for a joint confrontation with Yuwen.

Another official who supported the peace, Huangfu Wuyi (皇甫無逸), fled to Chang'an and surrendered to the newly established the Tang dynasty.

Emperor Gaozu was impressed and stated, "Xu Shiji remembers his lord and surrenders his accomplishments, and is really a pure-hearted subject."

In fall 619, Dou Jiande, then with the title of Prince of Xia, launched a major offensive, set to affirm his control of the territory north of the Yellow River, as a number of cities there had submitted to Tang.

Li Shiji agreed, and in winter 619, he attacked the city of Huojia (in modern Xinxiang, Henan), held by Wang Shichong (who had by that point had Yang Tong yield the throne to him, ending Sui and establishing a new state of Zheng) and captured much goods and persons to present to Dou, including Dou's childhood friend Liu Heita.

Dou agreed, and he sent his brother-in-law Cao Dan (曹旦) south across the Yellow River, joining forces with Li Shiji.

When Wang Shichong's son and crown prince, Wang Xuanying (王玄應), heard of this, he headed to Guan from Hulao, but Li Shiji repelled him, and then had Guo write a letter to Wei Lu (魏陸), Zheng's prefect of Ying Prefecture (滎州, also in modern Zhengzhou), to persuade Wei to surrender.

Later in 623, the general Fu Gongshi rebelled against Tang at Danyang (丹楊, in modern Nanjing, Jiangsu) and declared himself the Emperor of Song.

After Emperor Taizong took the throne, he made Li Shiji the commandant at Bing Prefecture (并州, roughly modern Taiyuan, Shanxi).

(Ashina Duobi himself fled further and was later captured by forces under the command of Emperor Taizong's cousin Li Daozong the Prince of Rencheng County.)

In 637, as part of Emperor Taizong's scheme to bestow prefectures on his relatives and great generals and officials as their permanent domains, Li Shiji's title was changed to Duke of Ying, and he was given the post of prefect of Qi Prefecture (蘄州, roughly modern Huanggang, Hubei), to be inherited by his heirs, but Li Shiji remained at Bing and did not actually report to Qi.

Soon, however, with many objections to the system, the strongest of which came from Zhangsun Wuji, Emperor Taizong cancelled the scheme, although Li Shiji's title remained Duke of Ying.

Emperor Taizong launched armies, commanded by five generals, including Li Shiji, to aid Eastern Tujue.

Further, on one occasion, when Li Shiji was attending an imperial feast, Emperor Taizong stated: "I am selecting, among the great achievers, one that I can entrust an orphan [(i.e., the Crown Prince)] to, and no one is more suitable than you are.

Emperor Taizong, after several months of preparations, launched a two-pronged attack against Goguryeo in winter 644, with Li Shiji in charge of the land army containing 60,000 soldiers, heading toward Liaodong Peninsula, and with Zhang Liang in charge of the navy numbering 40,000 soldiers, heading directly toward the Goguryeo capital Pyongyang.

In spring 645, Li Shiji reached You Prefecture (幽州, roughly modern Beijing), and then headed into Goguryeo territory.

Tang forces then continued heading southeast, toward Yalu River, putting Ansi (安市, in modern Anshan, Liaoning) under siege.

In 653, Emperor Gaozong bestowed the highly honorific title of Sikong (司空, Minister of Works) on Li Ji, who continued to be chancellor de facto.

Almost all high level officials opposed—on the account that Consort Wu had previously been a concubine of Emperor Taizong and therefore having her as a wife would be considered incest, and on the account that Empress Wang was from an honored clan while Consort Wu, while herself from a noble family, was not as highly born—with the conspicuous exceptions of Li Ji, Zhangsun Wuji, and Yu Zhining, each of whom was silent, although Zhangsun and Yu showed their disapproval.

Empress Wu soon became dominant at court, installing officials who favored her ascension in chancellor posts and carrying out a near complete purge of the officials who opposed her or showed disapproval, even including Zhangsun (who, as Emperor Gaozong's uncle, was a major advocate for his having been made crown prince), but Li Ji, not having opposed her, escaped such actions.

Meanwhile, the generals serving under him, Pang Tongshan (龐同善), Gao Kan (高侃), and Xue Rengui, also defeated Yeon Namgeon's forces.

However, the fleet commanded by Guo Daifeng (郭待封, Guo Xiaoke's son) ran into problems with food supplies, and wanted to seek aid from Li Ji, but was fearful that if his request fell into Goguryeo hands that his weakness would be revealed, so he wrote the request in code, written as a poem, and sent it to Li Ji.

I saw with my own eyes how Fang Xuanling and Du Ruhui worked hard all their lives and established their fame, but they encountered wicked descendants who overturned their clans, without further hope.

The Song dynasty historian Sima Guang, in his Zizhi Tongjian, stated: Li Ji, as a military commander, was full of strategies and capable of making excellent decisions.

In reprisal, Empress Dowager Wu destroyed Li Ji's tomb, posthumously stripped him of his titles, and slaughtered most, but not all, of his descendants.

Li Ji is one of the 32 historical figures who appear as special characters in the video game Romance of the Three Kingdoms XI by Koei.