Zhi Yao 知瑤 (also written 智瑤, died 453 BCE), also called Xun Yao 荀瑤 or Zhi Bo 知伯 (or 智伯) "the Earl of Zhi", posthumous title Zhi Xiangzi 智襄子 or Zhi Wenzi 知文子, was a nobleman in the state of Jin 晉 during the Spring and Autumn period 春秋 (770-5th cent. BCE). He was a great-grandson of Zhi Ying 知罃 and a grandson of Xun Li 荀躒, and so a member of the house of Zhi 知 (or 智).
The head of the house of Zhi acted as one of the Four Ministers Commander (siqing 四卿, the others being the head of the noble families of Zhao 趙, Wei 魏 and Han 韓) that had destroyed the noble families of Fan 范 and Zhonghang 中行 (all of them formerly called the Six Ministers Commander, liuqing 六卿), competitors for power in the state of Jin. These four families dominated the fate of the ducal house of Jin and even forced Duke Chu 晉出公 (r. 475-457) into exile, where he died.
Xun Yao, as the strongest of all nobles in Jin, besieged in 464 the capital of the state of Zheng 鄭. During this campaign, Zhi Bo insulted Zhao Wuxu 趙無恤 (Viscount Xiang of Zhao 趙襄子) as a coward. Zhi Bo is said to have become ever more arrogant towards the other nobles in the state of Jin. In 454, he even claimed some towns in the territory of Viscount Xiang of Zhao, yet the latter resisted and therefore ignited a fierce struggle for power.
Xun Yao first succeeded in winning the support of the viscounts of Wei and Han. The troops of the three houses besieged Jinyang 晉陽 (modern Taiyuan 太原, Shanxi), but Viscount Xiang was able to defend his seat for more than a year. He finally sent Zhang Mengtan 張孟談 (or Zhang Mengtong 張孟同) to the viscounts of Han and Wei to pursue them to change sides. The two men in fact decided supporting the brave Viscount Xiang and killed Xun Yao in a fight. His territory was divided among the three victors that were, from then on, called the Three Ministers Commander (sanqing 三卿), or the Three Jin (Sanjin 三晉), because they finally divided up the territory of the duke of Jin.