Famine upon famine, crushing taxes and eunuch corruption had drained the Han of its people’s loyalty.

When Dong Zhuo enthroned Emperor Xian and ruled by terror, the eastern lords formed a punitive coalition under Yuan Shao in 190.

Master of Xuzhou, Lü Bu had driven out Liu Bei and cycled through alliance and rupture with Yuan Shu, menacing Cao Cao’s eastern flank.

Yuan Shao, unifier of the four northern provinces, and Cao Cao, keeper of the Emperor — a showdown was only a matter of time.

When Liu Biao died in 208 and his heir surrendered Jing Province without a fight, Liu Bei at Xinye was suddenly cut off.

With Jing Province absorbed without a blow, Cao Cao drove south with a host recorded in the hundreds of thousands, plus the surrendered Jing navy.

When Cao Cao moved to cross Guanzhong, nominally against Zhang Lu of Hanzhong, the Xiliang warlords read it as a blade aimed at themselves.

In 215, with Cao Cao tied down in Hanzhong, Sun Quan raised a host recorded at a hundred thousand against the key fortress of Hefei — garrisoned by barely seven thousand under Zhang Liao, Yue Jin and Li Dian.

For the new master of Yi Province, Hanzhong was a knife at the throat — as long as Cao Cao held it, Shu lay open to invasion.

In 219, as Liu Bei took his royal title, Guan Yu rode the momentum north against Cao Ren at Fancheng.

Enthroned as emperor, Liu Bei declared war eastward — vengeance for Guan Yu and the recovery of Jing Province.

With Shu reeling from Yiling and Liu Bei’s death, the magnates and tribal leaders of Nanzhong — the far southwest — rose together, in contact with Wu.

Zhuge Liang’s first campaign in 228 achieved total surprise — three commanderies defected to Shu and the whole northwest trembled.

In 234 Zhuge Liang committed his whole army — a hundred thousand by the records — to his fifth and final campaign.

With Shu gone in 263 and Sima Yan replacing Wei with his new Jin dynasty in 265, only Jin and Wu remained.