Saylor.org's Ancient Civilizations of the World/Zhou (Chou) Feudalism and Cultural Change
Around 1046 BCE, King Wu, the leader of the Zhou (Chou), a subject people living in the west of the Chinese kingdom, overthrew the last king of the Shang Dynasty. King Wu died shortly after this victory, but his family, the Ji, would rule China for the next few centuries. Their dynasty is known as the Zhou Dynasty.
The Mandate of Heaven 
After overthrowing the Shang Dynasty, the Zhou propagated a new concept known as the Mandate of Heaven. The Mandate of Heaven became the ideological basis of Zhou rule, and an important part of Chinese political philosophy for many centuries. The Mandate of Heaven explained why the Zhou kings had authority to rule China and why they were justified in deposing the Shang dynasty. The Mandate held that there could only be one legitimate ruler of China at one time, and that such a king reigned with the approval of heaven. A king could, however, loose the approval of heaven, which would result in that king being overthrown. Since the Shang kings had become immoral—because of their excessive drinking, luxuriant living, and cruelty—they had lost heaven’s approval of their rule. Thus the Zhou rebellion, according to the idea, took place with the approval of heaven, because heaven had removed supreme power from the Shang and bestowed it upon the Zhou.
Western Zhou 
After his death, King Wu was succeeded by his son Cheng, but power remained in the hands of a regent, the Duke of Zhou. The Duke of Zhou defeated rebellions and established the Zhou Dynasty firmly in power at their capital of Fenghao on the Wei River (near modern-day Xi’an) in western China. The period in which the Zhou held undisputed power over China is known as the Western Zhou period. A number of important innovations took place in this period. The Zhou moved away from worship of Shangdi, the supreme god under the Shang, in favor of Tian (“heaven”). New advances in irrigation allowed more intensive farming, which in turn allowed the lands of China to sustain larger populations. Lands were farmed by peasants, who were controlled by the feudal system, the development of which was one of the most important innovations of this period.
After the Duke of Zhou stamped out local rebellions, he gave large holdings of land to nobles and generals who had proved loyal. These lands were similar to medieval fiefs in that they belonged to nobles, who in turn were under the authority of the king. This feudal system was known as the fengjian system, and allowed the Zhou to govern the huge expanse of China’s territory by giving regional power to nobles who would rule their lands in the name of the king. The land would be passed down within the family of the nobles, and the nobles could grant control of parts of their lands to lesser nobles in exchange for service and loyalty.
When the Duke of Zhou stepped down as the adviser and regent of King Cheng, China was united and at peace, leading to years of prosperity. This strong and prosperous state only lasted for about seventy-five years. Slowly, over time, the central power of the Zhou monarchs weakened. The lords of the fiefs originally bestowed by the Zhou came to equal the kings in wealth and power. The old bonds of loyalty weakened, and the lords of the fiefs actively competed with the Zhou kings for power. These fiefs became largely independent, and known as individual states. In 711 BCE, a rebellious noble, the Marquess of Shen, joined forces with invading barbarians, known as the Quanrong, to defeat the Zhou King You. Supposedly none of the nobles came to the king’s defense. King You was killed, and the Zhou capital was sacked by the barbarians. This brought an end to the Western Zhou period.
Eastern Zhou: Spring and Autumn Period 
With this disaster, the capital was moved east to Chengzhou, near modern-day Luoyang, and the Zhou abandoned the western regions. Thus, this period is known as the Eastern Zhou period. The new kings of the Zhou continued to lose power, and their authority became limited to the area around the capital. They were still the nominal kings of China, but in reality the local nobles ruled their own lands as kings in all but name. China had split up into a patchwork of small states, with the Zhou king as ceremonial leader but having no real power. The Mandate of Heaven, which specified that there could only be one supreme leader of China, was widely accepted, so no one overthrew the Zhou Dynasty. However, the dynasty simply became irrelevant. In the meantime, many of the local nobles went to war with each other as they vied for power. Though there are a total of 148 states mentioned in historical sources in this period, four states—Qi, Qin, Jin, and Chu—dominated China in the early Eastern Zhou period. They constantly changed alliances as they vied for control. China was nearly always at war.
Despite political fragmentation, this was also a period of great intellectual development in China. The Spring and Autumn period, the first half of the Eastern Zhou period, is named after the Spring and Autumn Annals, an important Chinese history text which narrated events on a year by year basis. This marks the beginning of China’s recorded history, and we can rely on written sources, instead of legend, from this time on. The Spring and Autumn period was also the time of the Hundred Schools of Thought—the golden age of Chinese philosophy. This was the period in which some of the most important Chinese philosophers lived, many of whom were patronized by the rulers of the small states that dominated China.
Perhaps foremost among these philosophers was Confucius. He looked back on the Western Zhou period, with its strong centralized state, as an ideal. He was pragmatic, and sought to reform the existing government, encouraging a system of mutual duty between superiors and inferiors. Confucius stressed tradition and believed that an individual should strive to be virtuous and good mannered, and to fit into his place in society.
Another important philosopher in this period was Laozi, who founded Daoism (Taoism). It is uncertain if Laozi actually existed, but the philosophy attributed to him certainly developed during this time. Daoism advocated that the individual should follow the way (dao) of the universe and act in accordance with nature. Daoism stressed passivity and wu wei—that is, nonaction. Daoism was strictly individualistic, as opposed to Confucianism, which advocated acting as society expected.
Although Confucianism and Daoism are the most enduring Chinese philosophies to this day, even more important in this early period was a lesser-known philosophy called Legalism, which held that humans are inherently bad and need to be kept in line by a strong state. According to Legalism, the state was everything, far more important than the individual. While Legalism held that laws should be clear and public, and that everyone should be subject to the law, it also contended that rulers had supreme power and must use secret techniques and tactics to remain in power. Legalism was generally in competition with Confucianism, which advocated a just and reciprocal relationship between the state and its subjects.
Another major competitor with Confucianism was the philosophy of Mohism, developed by Mozi during the Spring and Autumn period. Mohism advocated universal love—that is, deep concern for all people. It held that all were equal, and that power should be based not on ancestry or tradition, but on merit. Developing in a period of constant rivalry between states, Mohists were opposed to offensive warfare, believing that it was the cause of many of the contemporary problems in China, and many adherents of the philosophy traveled widely, offering their services to defend any state that was being attacked by another.
The Spring and Autumn Period is generally held to have come to an end when the state of Jin, one of the most powerful at the time, collapsed. The state broke up into three smaller states: Han, Wei, and Zhao. About the same time, the state of Yue (a new state) became powerful. Thus, with seven rival states—Han, Wei, Zhao, Yue, Chu, Qi, and Qin—China entered a period known as the Warring States period, as each state vied for complete control. In the middle of all this, the Zhou kings could only look on, powerless. The Zhou kings continued to hold the Mandate of Heaven, and thus acted as the sacred rulers of China, but by the Warring States period the rulers of the independent states had begun to use the title of king (wang).
Eastern Zhou: Warring States Period 
The Warring States period gets its name from a history, called Strategies of the Warring States, written about the period during the later Han Dynasty. The seven major Chinese states were in constant competition in this period. Since none of the states wanted any one rival to become too powerful, if one state became very strong, the others would join forces against it, so no state could achieve dominance. This led to nearly 250 years of inconclusive warfare. In this period, warfare became larger and larger in scale. Expensive chariots became less useful, while the invention of the crossbow (which was cheap to make and required little training) meant that masses of expendable infantry became more desirable. As a result, peasants were conscripted into the military more often. This period also saw the widespread adoption of iron tools and weapons, which were significantly stronger than their bronze counterparts. Thus, the Warring States period is the time when China fully entered the Iron Age.
The Warring States period also saw the further development of the philosophical movements that originated in the Hundred Schools of Thought of the Spring and Autumn period. Mencius further developed Confucian philosophy, expanding upon its doctrines. Daoism, Mohism, Legalism, and other philosophies that had their earliest origins in the Spring and Autumn period became more developed (and took the only forms in which we know them, since the earliest texts we have are from the Warring States period). It was also in this period that archaic writing gave way to a far more recognizable form of Chinese script.
Though the military rivalries and alliances in the Warring States period were complex and ever changing, over time the Qin state slowly emerged as the most powerful. Qin was in the western-most part of China, controlling the area where the old Western Zhou capital had been. In 249 BCE, the Zhou line died out, leaving no more kings to hold the Mandate of Heaven. However, within less than thirty years of this event, the Qin state, led by Ying Zheng (later known as Qin Shi Huang) would conquer all its rivals, and by 221 BCE unite China once more. With the Zhou gone, Ying Zheng claimed the Mandate of Heaven and created a new dynasty, the Qin Dynasty. Instead of taking on the title of king, however, he bestowed upon himself a far grander title— Emperor of China.
- The Zhou Dynasty overthrew the Shang Dynasty, and developed the Mandate of Heaven. This justified their deposition of the Shang because it held that although there could be only one ruler of China, if such a ruler became corrupt he would be overthrown.
- Under the Zhou, the fengjian system developed, in which nobles were given land to rule in a feudalistic manner, governing their own fiefs under the authority of the king. As the power of the Zhou kings weakened, the nobles who ruled their own fiefs became increasingly independent, as these fiefs turned into small states.
- In 711 BCE, a rebellion by a noble combined with a barbarian invasion overthrew the Zhou king. Though the Zhou Dynasty survived, it moved its capital eastward. This was the end of the Western Zhou period, and the beginning of the Eastern Zhou period, when the Zhou kings became little more than powerless figureheads.
- The first part of the Eastern Zhou period was the Spring and Autumn period. This period saw warfare between the small Chinese states, but also the blossoming of Chinese philosophy in the Hundred Schools of Thought.
- Some of the most important philosophies to develop in the Eastern Zhou period were Confucianism, Mohism, Daoism, and Legalism.
- The second part of the Eastern Zhou period was the Warring States period, which saw intense warfare between the seven surviving Chinese states. In 221 BCE, the Qin emerged victorious, defeating the other states and unifying China once more.
"The Zhou Dynasty" (Saylor) http://www.saylor.org/site/wp-content/uploads/2012/10/HIST101-3.2.2-ZhouDynasty-FINAL1.pdf