Kingdom in southwest China during the third century A.D.. The country was established by Liu Bei after the Han Dynasty lost the Mandate of Heaven. It made up one of the three kingdoms during the aptly name Three Kingdoms period of China.
The land that became Shu was conquered by Liu Bei from the former leader Liu Zhang. It was an easily defended, moderately wealthy land. The area become the staging ground for invasions of Wei, and once the Man tribes to the south where succesfully conquered, became the chief rival of Wei in the quest of unification.
Unfortunately Shu was never trully a match for the rich heavily populated areas of Wei, thus every mistake made was a glaring blow to the stability of the nation. When the kingdom lost Liu Bei, it was the beginning of the end. Zhuge Liang's promise to carry out the wishes of his former lord caused him to engage in five campaigns against Wei, each one weakening the kingdom further.
Though Shu, then under Liu Bei's son Liu Chan was the first of the two kingdoms (Wu and Shu) to fall to Wei, it was in reality the final thing standing between Wei and the unification of China. Once Shu fell, the fall of Wu was a foregone conclusion. The main thing that had kept the land of Wu free from conquest had been the threat from Shu. With Shu gone, the descendents of Sima Yi where easily able to gain the throne of a united China.