The re-unification of China proper under the Sui brought the Northern and Southern dynasties era to a close, ending a prolonged period of political division since the War of the Eight Princes.

The dynasty was founded by Yang Jian (Emperor Wen), who had been a member of the military aristocracy that had developed in the northwest during the prolonged period of division.

By the dynasty's mid-point, the state experienced considerable prosperity, enjoying a vast agricultural surplus that supported rapid population growth.

[3] The canal linked Luoyang in the east with Chang'an in the west, with the eastern economic and agricultural centres towards Jiangdu (now Yangzhou, Jiangsu) and Yuhang (now Hangzhou, Zhejiang), and with the northern frontiers (near modern Beijing).

While the initial motivations of the canal were improving grain shipments to the capital and military logistics—including the transportation of troops—the new, reliable inland route would ultimately facilitate domestic trade, the flow of people, and cultural exchange for centuries.

Particularly, under Emperor Yang, heavy taxation and compulsory labour duties would eventually induce widespread revolts and brief civil war following the fall of the dynasty.

After crushing an army in the eastern provinces, Yang Jian usurped the throne from the Northern Zhou rulers, and became Emperor Wen of Sui.

Having won the support of Confucian scholars who held power in previous Han dynasties (abandoning the nepotism and corruption of the nine-rank system), Emperor Wen initiated a series of reforms aimed at strengthening his empire for the wars that would reunify China.

In his campaign for southern conquest, Emperor Wen assembled thousands of boats to confront the naval forces of the Chen dynasty on the Yangtze River.

The city was razed to the ground, while Sui troops escorted Chen nobles back north, where the northern aristocrats became fascinated with everything the south had to provide culturally and intellectually.

Although Emperor Wen was famous for bankrupting the state treasury with warfare and construction projects, he made many improvements to infrastructure during his early reign.

The large agricultural surplus supported rapid growth of population to a historical peak, which was only surpassed at the zenith of the Tang dynasty more than a century later.

The capital of Daxing (Chang'an, modern Xi'an), while situated in the militarily secure heartland of Guanzhong, was remote from the economic centres to the east and south of the empire.

Emperor Wen initiated the construction of the Grand Canal, with completion of the first (and the shortest) route that directly linked Chang'an to the Yellow River (Huang He).

Nevertheless, the celebrated "Reign of Kaihuang" (era name of Emperor Wen) was considered by historians as one of the apexes in the two millennium imperial period of Chinese history.

[22]: 30  Simocatta also provided cursory information about the geography of China, its division by the Yangzi River and its capital Khubdan (from Old Turkic Khumdan, i.e. Chang'an) along with its customs and culture, deeming its people "idolatrous" but wise in governance.

Between these policies, invasions into China from Turkic nomads, and his growing life of decadent luxury at the expense of the peasantry, he lost public support and was eventually assassinated by his own ministers.

During the last few years of the Sui dynasty, the rebellion that rose against it took many of China's able-bodied men from rural farms and other occupations, which in turn damaged the agricultural base and the economy further.

[26][dubious – discuss] Men would deliberately break their limbs in order to avoid military conscription, calling the practice "propitious paws" and "fortunate feet.

"[26][dubious – discuss] Later, after the fall of Sui, in the year 642, Emperor Taizong of Tang made an effort to eradicate this practice by issuing a decree of a stiffer punishment for those who were found to deliberately injure and heal themselves.

Again, like the Great Wall works, the massive conscription of labour and allocation of resources for the Grand Canal project resulted in challenges for Sui dynastic continuity.

Most notably, Zhiyi founded the Tiantai school, and completed the Great treatise on Concentration and Insight, within which he taught the principle of "Three Thousand Realms in a Single moment of Life" as the essence of Buddhist teaching outlined in the Lotus Sutra.