Su Qin

Su Qin, a strategist from the School of Diplomacy, traveled to the courts of Zhao, Han, Wei, Yan, Qi, and Chu, persuading them to form a 'Vertical Alliance' (hezong) against the expansionist state of Qin. This alliance temporarily united the six states and checked Qin's aggression.

Su Qin was appointed chancellor of all six allied states simultaneously, a unique achievement in Chinese history. He coordinated their military and diplomatic strategies, though the alliance was fragile and ultimately failed due to internal rivalries.

Su Qin's career exemplified the School of Diplomacy (Zonghengjia), which emphasized persuasion and alliance-building over military force. His strategies influenced later diplomatic thought and were recorded in the 'Intrigues of the Warring States'.

Su Qin was assassinated by rivals in Qi who accused him of being a spy for Yan. According to some accounts, he had himself publicly executed to expose the assassins, a ruse that led to their capture and execution after his death.