Hara, Yōhei(2003)圖解三國時代, p. 251(in Mandarin, translated from Japanese), ISBN 9867881729
Etymology
An official position which came into being during the Warring States Period, and reached the zenith of its influence during the Han dynasty. At first, the person in this position was the supreme military commander (modern equivalent ~ Chairman of the Joint Chiefs of Staff). During the later half of the Han dynasty, he also took over the day to day executive affairs of government (modern equivalent ~ Hideki Tojo). During the Three Kingdoms period, the position again became military related (modern equivalent ~ United States Secretary of Defense).