While scholars have identified several different dates as marking the beginning of the Warring States period, Sima Qian's choice of 475 BC is the most often cited.

Hundreds of smaller polities coalesced into seven major states which included: Chu, Han, Qin, Wei, Yan, Qi and Zhao.

The Spring and Autumn period led to a few states gaining power at the expense of many others, the latter no longer able to depend on central authority for legitimacy or protection.

The last decades of the Spring and Autumn era were marked by increased stability, as the result of peace negotiations between Jin and Chu which established their respective spheres of influence.

This allowed other clans to gain fiefs and military authority, and decades of internecine struggle led to the establishment of four major families, the Han, Zhao, Wei and Zhi.

The Jin division created a political vacuum that enabled during the first 50 years expansion of Chu and Yue northward and Qi southward.

In 403 BC, the court of King Weilie of Zhou officially recognized Zhao, Wei and Han as immediate vassals, thereby raising them to the same rank as the other warring states.

This conflict marked the end of the power of the united Jins and the beginning a period of shifting alliances and wars on several fronts.

The demonstrated military prowess also had a calming effect on Qi's own population, which experienced great domestic tranquility during Wei's reign.

The strategy was a success; the Wei army hastily moved south to protect its capital, was caught on the road and decisively defeated at the Battle of Guiling.

The battle is remembered in the second of the Thirty-Six Stratagems, "besiege Wei, save Zhao"—meaning to attack a vulnerable spot to relieve pressure at another point.

Domestically, King Hui patronized philosophy and the arts, and is perhaps best remembered for hosting the Confucian philosopher Mencius at his court; their conversations form the first two chapters of the book which bears Meng Zi's name.

This changed during the reign of Duke Xiao, when prime minister Shang Yang made centralizing and authoritarian reforms in accordance with his Legalist philosophy between the years 356 and 338 BC.

The rise of Qin was recognized by the royal court, and in 343 BC the king conferred the title of Count (伯 Bó) on Duke Xiao.

The generals from the Battle of Guiling met again (Sun Bin and Tian Ji versus Pang Juan), using the same tactic, attacking Wei's capital.

The state rose to a new level of power around 389 BC when King Dao of Chu (楚悼王) named the famous reformer Wu Qi as his chancellor.

After the failure of the first vertical alliance, Su Qin eventually came to live in Qi, where he was favored by King Xuan and drew the envy of the ministers.

The Qin army led a direct invasion into Wei by besieging its capital Daliang but soon realized that the city walls were too tough to break into.

Upon realizing the situation, King Jia of Wei hurriedly came out of the capital and surrendered it to the Qin army in order to avoid further bloodshed of his people.

Chu lost the initiative and could only sustain local guerrilla-style resistance until it too was fully conquered with the destruction of Shouchun and the death of its last leader, Lord Changping, in 223 BC.

[citation needed] Near the beginning of the Warring States period there is a shift from chariots to massed infantry, possibly associated with the invention of the crossbow.

For the Warring States period the following figures for the military strengths of various states are reported: For major battles, the following figures are reported: Many scholars think these numbers are exaggerated (records are inadequate, they are much larger than those from similar societies, soldiers were paid by the number of enemies they killed and the Han dynasty had an interest in exaggerating the bloodiness of the age before China was unified)[weasel words].

The bloodshed and misery of the Warring States period goes a long way in explaining China's traditional and current preference for a united throne.

The first official native Chinese cavalry unit was formed in 307 BC during the military reforms of King Wuling of Zhao, who advocated 'nomadic dress and horse archery'.

Professional warriors of that era used the military concepts of "Master" Sun Tzu and created several successful "Ge Dou" martial schools.

At the same time, the constant conflict and need for innovative social and political models led to the development of many philosophical doctrines, later known as the Hundred Schools of Thought.

[21] Legalism created by Shang Yang in 338 BC, rejected all notions of religion and practices, and believed a nation should be governed by strict law.

Power was centralised by curbing the landed aristocrats and sinecures and creating a new hierarchy based on meritorious service to the state, which were drawn from the lower rungs of society.

[citation needed] A bundle of 21 bamboo slips from the Tsinghua collection dated to 305 BC are the world's earliest example of a two digit decimal multiplication table, indicating that sophisticated commercial arithmetic was already established during this period.

The Warring States period saw the proliferation of iron working in China, replacing bronze as the dominant type of metal used in warfare.