Wu Zetian usurped Tang Lizhou and established himself as emperor, and also created a character for himself ,曌," calling himself "Wu Cao". Although Wu Zetian became emperor, she knew that her name was not right, her words were not smooth, and she was always afraid that someone would overthrow her. So the cool officials were reused to encourage those who reported rebellion. In this way, many people have been wrongfully killed. One of the brave side generals was also framed, and because of his difficult arguments, he could only hang himself.
This general, black tooth Changzhi (630-689), was a Baekje man who was good at using soldiers and was "brave and strategic". When Su Dingfangke Baekje was in Baekje, he led his troops to surrender to Tang. After that, Black Tooth Changzhi became a brave frontier general of the Tang Dynasty, and he once led 3,000 elite cavalry to attack the Tubo army camp at night, defeating the Tubo army, killing 2,000 people and capturing tens of thousands of sheep and horses. Later, he led more than 200 cavalry to attack the Turkic cavalry as the vanguard, killing the Turkic army and taking advantage of the night to escape.
Black Tooth Changzhi killed the enemy at the border pass to defend the Tang Dynasty, but someone on the other side of the court beat him. In the first year of Yongchang (689), the cool official Zhou Xing and others falsely accused black tooth Changzhi of plotting against the right eagle Yang general Zhao Huaijie and others. Wu Zetian did not ask qingju about the soap, and ordered the arrest of Black Tooth Changzhi. Black Tooth often has a hard time arguing, knowing that if he is caught, he will be tortured and interrogated, and he will be beaten into a confession, rather than that, it is better to die. As a result, black teeth often hang themselves. During Wu Zetian's heavy use of cheese officials, there were many people like Black Tooth Changzhi.