In the summer of the eleventh year of the Jian'an Era, in the fifth month, Liu Bei summoned Liu Zhang to court to serve as an official, but Liu Zhang refused. Liu Bei therefore appointed Zhang Fei as commander-in-chief and sent him to invade Shu with an army of eighty thousand.
This campaign against Shu came a full six years earlier than Liu Bei's original invasion of Shu, and the troops Liu Bei sent into Shu were no longer merely ten thousand strong.
After the great war in Guanzhong, three years of rest and recuperation had made Liu Bei's forces far stronger than before. Moreover, Qin Tian had reopened the Protectorate of the Western Regions, making commerce and trade within their territory even more prosperous.
By the eighth year of the Jian'an Era, cotton cultivation in Huainan, Qingzhou, and Xuzhou had already surpassed three million mu. Vast quantities of cotton were transported by ship to Jiangdong.
There, under the hands of Jiangdong's female workers, it was woven into cotton cloth and shipped to Chang'an and Luoyang. While meeting domestic demand, it was also sold to Central Asia through the Silk Road.
Besides cotton cloth, exports of tea, porcelain, glass, salt, silk, white sugar, and other goods had plundered vast quantities of gold from Southeast Asia.
All of this gave Liu Bei's forces military spending that crushed the warlords of the age, even somewhat surpassing the days of Emperor Ling, far beyond anything Liu Zhang's troops could compare with.
Likewise, as the slave trade flourished, tens of thousands of Nanyang slaves were transported each year to Jiangdong and Jiaozhi. These slaves were used for mining, land reclamation, farming, and sale.
This left Liu Bei's forces abundantly supplied. Whether in arms and armor, morale, equipment, or organization, they had almost surpassed the