The School of Diplomacy or School of Vertical and Horizontal Alliances (縱橫家/纵横家; Zonghengjia) specialized in diplomatic politics; Zhang Yi and Su Qin were representative thinkers.
The historian Li Ling mentions this in his simplified version "Sun Tzu" in the "Espionage" chapter, viz “When the Zhou flourished, Lu Ya was in Yin" followed by the sentence, “When the Yan State flourished, Su Qin was in Qi”. Li Ling believes that this "Sun Tzu" is not the same as the one handed down to later generations and is clearly the history of the late Warring States period.
Qin | Qin Shi Huang | Qin Dynasty | Qin (state) | Qin dynasty | Qin Empire | Former Qin | Qin Kai | '''Qin'''huangdao | Qin Guangrong | Wen Qin | Qin Yi | Qin Ming | Qin Lang | Qin Kai (general) | Qin Kai (diver) | Qin Er Shi | Qin'an County | King Wu of Qin | Duke Xiang of Qin | Duke Mu of Qin |
Both Su Qin of the Vertical Alliance clique and Zhang Yi of the Horizontal Alliance clique issue many plans and schemes that are politically subjective.