Zhang Yi (Warring States period)

Zhang Yi (before 329 BC – 309 BC) was a Chinese military strategist and philosopher. He was born in the Wei state during the Warring States period of Chinese history. He was an important strategist in helping Qin to dissolve the unity of the other states, and hence pave the way for Qin to unify China. He was an advocate of the Horizontal Alliance to combat Su Qin's Vertical Alliance. Both were said to be disciples of Guiguzi and adherents of the School of Diplomacy.