Zhi Yao (Chinese: 知瑤), Xun Yao (Chinese: 荀瑤), or Zhi Boyao (Chinese: 知伯瑤), posthumously known as Zhi Xiangzi (Chinese: 知襄子; literally: "Viscount Xiang of Zhi"), was the ruler of Zhi, a vassal state of Jin during the late Spring and Autumn period. He was the son of Zhi Shen. He was the last Zhongjunjiang (Prime minister) of Jin before its partition.
Zhi Yao's dramatic death was a known topic in Chinese history. As the dominant vassal state, he asked Kangzi of Han, Huanzi of Wei and Xiangzi of Zhao to cede their lands to the Zhi clan. Han and Wei did so according to Zhi's wish. However, Zhao refused to give lands to Zhi clan. Xiangzi was triggered and led his army, along with the army from Han and Wei, laid siege on the Zhao capital Jinyang (modern Taiyuan). The siege lasted two years before it came to a dramatic end. Zhao conspired with Han and Wei's ruler, Xiangzi was betrayed by his own allies and defeated. Zhao decapitated Zhi Yao and massacred his entire family. After the fall of Zhi clan, no vassals in Jin could once again match the power of Zhao, Han, and Wei. The Duke of Jin was consequently turned into a figurehead. This eventually led to the Partition of Jin and the establishment of Han, Zhao and Wei as independent states acknowledged by the Zhou dynasty King of China.
When choosing Xiangzi as his successor, Xuanzi of Zhi was warned by his clansman Zhi Guo who believed that Xiangzi's personality did not fit the quality of a ruler. However, Xuanzi dismissed Guo's opinion.
In 472 BC. The third year of Duke Chu of Jin's rule. Xiangzi led his army invaded the state of Qi. He managed to defeat Qi's troops in the battle of Liqiu. Zuo Qiuming recorded this battle in his work Zuo Zhuan. In the Zuo Zhuan, it is shown that Xiangzi of Zhi resented oracles of I Ching because Zhi believed in his own power. In 468 BC, Xiangzi of Zhi invaded the state of Zheng. Zheng's retainer Sihong then asked Qi for reinforcement. With the intervention of Qi, Zhi had to abandon his plan of invading Zheng. In 464 BC, Zhi once more entered Zheng's realm with the troops from Zhi clan and Zhao clan. Zheng's Sihong organized resistance against them.