The Warring States period (Zhanguo 戰國, 5th cent.-221 BCE) is the later part of the so-called Eastern Zhou period (Dongzhou 東周, 770-221 BCE). It is characterized by an increased centralisation and bureaucratisation within the regional states of the Zhou kingdom. The kings of the Zhou dynasty 周 (11th cent.-221 BCE) had become politically - and also jurisdictionally - irrelevant. The regional rulers (zhuhou 諸侯), former vassals of the Zhou, had become independant rulers that one after the other adopted the title of "king" (wang 王) that was formerly reserved to the Zhou dynasty (and the rulers of the non-Chinese states of Chu 楚, Wu 吳 and Yue 越 in the south).

The ancient system of the regional states to employ relatives of the ruling houses as ministers was replaced by a system of appointing competent persons irrespective of their social background. The ancient nobility moved socially downwards, while commoners had the chance to raise to highest offices. The period has been given the name of "Warring States" because warfare increased in intensity. Armies of that period consisted of huge contingents of conscripts, were often commanded by professional generals, and served not only to defeat an enemy in punitive campaigns, but to destroy his country. New weapons like halberds (ji 戟) and crossbows (nu 弩) came up, chariots (zhanche 戰車), cavalry (qibing 騎兵) and archers supported the infantry that was protected by armour and iron helmets.

States like Han 韓 and Chu were the first to produce high-quality iron and steel weapons. The Warring States erected garrisons and fortification walls (changcheng 長城 "long walls") along their frontiers. Military advisors like Su Qin 蘇秦 gave instructions how to defeat foreign armies, or much better, how to make territorial gains without fighting. The armies of the Warring States were much larger than before. The state of Zhao 趙 brought more than 40.000 men up against Qin 秦, while Qin itself recruited 60.000 soldiers for the war against Chu 楚. The objective was to destroy as much military force as possible, and some prolonged battles saw more than ten thousand casualties.

War expenditure was correspondingly high and could only be met if the fighting states had prospering economies. Smaller regional states that could not rely on the necessary funds to maintain such large armies were therefore gradually swallowed up by the larger states. In the end, seven states (the "seven strong" qixiong 七雄) dominated the Zhou empire, namely Qin 秦, Qi 齊, Yan 燕, Chu 楚, Zhao 趙, Wei 魏 and Han 韓. They fought against each other in changing coalitions of the "vertical" (zong 縱) type or the "horizontal" (heng 橫) type, the former formed between states from the north and states of the south (for instance, Zhao, Han and Chu), the latter between states of the west and such from the east (for instance, Qi and Qin).

The Warring States period begins, according to one definition, with the dissolution of the state of Jin 晉 by the regional rulers of Zhao, Wei and Han (the "Three Jin" Sanjin 三晉) in 376, and ends with the conquest of the state of Qi by Qin and the subsequent creation of the empire of Qin 秦 (221-206 BCE). Other definitions fix the beginning of the Warring States period as the year 453, when the three viscounts (zi 子) of Han, Wei and Zhao extinguished all other lateral lines to the house of Jin, or 403, when King Weilie of Zhou 周威烈王 (r. 426-402) bestowed upon the viscounts of Han, Wei and Zhao the title of marquis (hou 侯).

The Warring States period is also characterised as a period of flourishing philosophies, some of them centering on state and society (Confucians, legalists, Mohists), others on the practical art of coalitions (coalition advisors) or warfare (military strategists), others on the individual and its position in the cosmos (Daoism, "hedonists", logicians), and some on the correlation between man and the phenomena of nature (Yin-Yang thought, Five Agents theory). These different currents of thought were called the "hundred schools" (baijia 百家).

The Warring States period began with the brutal extinction of the ruling house of Qi 齊 (the house of Jiang 姜) by the house of Tian 田. The Tian family took over the rulership of Qi in 481. In the small state of Lu 魯, already in 562 BCE the three Huan families (Sanhuan 三桓), lateral lines of the ducal house of Ji 姬, usurped power. At the beginning of the 5th century, five noble families in the state of Jin 晉 began to engage in a civil war for domination. Three of them, the houses of Wei 魏, Han 韓 and Zhao 趙, finally overcame their rivals and founded their own states, destroying and dividing Jin. In 424 BCE they mutually recognized their independence. The king of Zhou only recognized this partition in 403 BCE.

At the beginning of the Warring States period the house of Zhou saw a partition into two branches. King Jing's 周景王 (r. 545-521) great-grandson King Ai 周哀王 (r. 441) was killed by his brother Shuxi 叔襲 who usurped the throne and was himself killed five months later by a younger brother called Wei 嵬. Shuxi is known as King Si 周思王 (r. 441), Wei as King Kao 周考王 (r. 441-426).

Perhaps in order to forestall a further usurpation, King Kao invested a younger brother, Prince Jie 揭, as ruler over the territory of Henan 河南 and bestowed on him the title of duke (gong 公), with the intention to entrust him with the function of the former "Duke of Zhou" 周公 as a kind of Chief Counsellor. While the kings resided in the eastern part of the kingdom, in Gong 鞏 (modern Gongxian 鞏縣, Henan), since the times of King Jing, Duke Jie resided in the west, in the ancient capital Luoyang 洛陽 (Chengzhou 成周). Duke Jie was therefore called the "Duke of West Zhou" 西周 (not to be confounded with the ancient Western Zhou dynasty!). His posthumous title is Duke Huan of West Zhou 西周桓公. His dynastic line was continued with Duke Wei 西周威公 and Duke Hui 西周惠公. In fact, King Kao had handed over the keys to power to his younger brother, while he himself retained the merely honorific title of king. A younger son of Duke Hui of West Zhou, Prince Ban 班, finally took over the eastern part of the royal domain and replaced the line of King Kao. Prince Ban is therefore posthumously known as Duke Hui of East Zhou 東周惠公.

During the reign of King Lie 周烈王 (r. 375-369 BCE), the grand astrologer (taishi 太史) Dan 儋 travelled to the court of Duke Xian of Qin 秦獻公 (r. 385-362) and prognosticated that the states of Qin and Zhou would unite, and the strongest prince would appear as the ruler of China. Duke Xian indeed became the de-facto hegemonial lord (ba 霸), although this institution was not any more officially used like during the Spring and Autumn period 春秋 (770 - 5th cent. BCE). King Xian of Zhou 周顯王 (r. 369-321) honoured Duke Xiao of Qin 秦孝公 (r. 362-338) with sacrificial meat presented to the ancient Kings Wen 周文王 and Wu 周武王 of Zhou. The Duke of Qin, as highest leader of the regional rulers, in 344 assembled the regional rulers in the royal domain. In spite of all these favourable treatments by the king of Zhou, the ruler of Qin adopted the title of king in 325. In the consequence, the rulers of most of the larger states likewise called themselves king.

Rise and decline of the state of Wei

At a time when several regional states had already begun to realize structural reforms, the marquis of Wei was the first ruler who adopted the title of king (wang 王) that was actually reserved to the king of Zhou (and had been used since long by the rulers of the semi-barbarian states of Chu, Wu and Yue in the south). This was King Hui of Liang 梁惠王 (r. 379-335).

During the reign of the marquesses Wen 魏文侯 (r. 424-387) and Wu 魏武侯 (r. 386-371) Wei had expanded to east and west, destroyed in 408 the shortlived state of Zhongshan 中山 and several times defeated Qin with the generals Li Kui 李悝 and Wu Qi 吳起. In the mid-4th century Wei had become the dominating state of the Central Plain, attacked Song 宋, Wei 衛, Han and Zhao. In 353 Wei sacked Handan 邯鄲 (today in Hebei), the capital of Zhao but was then defeated at Guiling 桂陵 (modern Caoxian 曹縣, Shandong) by Qi that supported his ally Zhao.

In 344, Wei organized a state conference at Fengze 逢澤 (near modern Kaifeng 開封, Henan) and forced the regional rulers to assemble at the Mengjin Ford 孟津 to cherish the king of Zhou. But at the same time, the marquis of Wei (i. e. King Hui of Liang) declared himself king. The highlight of the new king's power did not last for long: In the battle of Maling 馬陵 (near modern Fanxian 范縣, Henan) in 341, the army of Qi (led by Tian Ji 田忌 and Sun Bin 孫臏) destroyed the army of Wei (led by Prince Shen 太子申 and Pang Juan 龐涓) and shortly after lost territories to Qin in the west. Qin thereupon sent out general Shang Yang 商鞅 and defeated Wei once more. King Liang had to shift his capital more to the east. In 334, he met with King Wei of Qi 齊威王 (r. 378-343) and accepted this eastern lord as a king (formerly a duke). Wei and Qi were now the two dominating states of the Central Plain. After the death of King Hui, Wei gradually lost its dominant position under the increasing attacks of Qin from the west.

The growing power of Qin

Strengthened by the reforms of Shang Yang under Duke Xiao 秦孝公 (r. 361-338) Qin had become a serious opponent for the states in the Central Plain. In 325, the duke of Qin adopted the title of king (King Huiwen of Qin 秦惠文王, r. 337-311). But Gongsun Yan 公孫衍 from Wei proposed to forge an alliance (meng 盟) against the newcomer. Zhao, Han, Yan 燕, and Chu united with Wei but were defeated by Qin in 318. The "wolf" from the west, as Qin was called, almost annually attacked border towns of Zhao, Han and Wei and proved its definitive military superiority.

The next step was to weaken Chu, the powerful state of the south. Chu lost several battles and had to give up much territory in favour to Qin. In the west, Qin successfully fought against the Rong 戎 tribes of Yiqu 義渠 and opened the way to the Gansu corridor. In 316, internal quarrels had weakened the non-Chinese state of Shu 蜀 in the Sichuan Basin. Qin took its chance, had its armies crossed the Qinling Range 秦嶺, and occupied the fertile region that would prove to be an ideal base for the conquest of Chu.

The competition between Yan and Qi

The state of Yan in the northeast (around modern Beijing) was likewise weakened by internal succession struggles when Qi decided to send out Tian Zhang 田章 with an army to conquer some territory of Yan. In 314, after two months of campaigning, Qi destroyed the army of Yan but withdrew because of further resistance. King Wuling of Zhao 趙武靈王 (r. 325-299) sent a relief army to support the Crown Prince of Yan and enthroned him (King Zhao of Yan 燕昭王, r. 311-279). With the assistance of Yue Yi 樂毅, the state of Yan was able to gain back its economical and military strength.

Qi as the powerful state in the east created an alliance with Han, Wei and Qin to attack Chu in the south in 301, and Chu was defeated. Five years later Qi concluded an alliance with Han, Wei, Zhao and Song to punish Qin, and for the first time, Qin was defeated and had to give back formerly conquered territory.

In the battle of Huanzhiqu 桓之曲 (Quan zhi nan 權之難 "difficulties of Quan"), Qi again defeated the army of Yan. In 288 the rulers of Qi and Qin decided to both adopt the title of emperor, the king of Qin being the Emperor of the West (Xidi 西帝), that of Qi the Emperor of the East (Dongdi 東帝), yet these designations were given up shortly after. Two years later, Qi destroyed the statelet of Song that had still been quite strong until then. Zou 鄒 and Lu immediately declared their loyalty to Qi.

In 284, Yan allied with the states Wei, Han, Zhao, Qin, and Chu to attack Qi. Qi was defeated, the capital occupied, and the king was murdered. The remaining court withdrew to the small city of Ju 莒. General Tian Dan 田單 took revenge when the new ruler of Yan, King Hui 燕惠王 (r. 278-272) replaced Yue Yi by general Qi Jie 騎劫, who proved to be a less competent leader. Tian Dan defeated Qi Jie, reconquered the capital and helped King Xiang of Qi 齊襄王 (r. 283-265) to the throne.

The downfall of Chu and the rise of Zhao

The "semi-barbarian" state of Chu, populous and fertile, had become one of the most powerful states of the Warring States era and reached its apogee with the destruction of the state of Yue by King Huai 楚懷王 (r. 328-299). Chu, Qin and Qi competed for the domination in China. King Huai was allured to visit the court of Qin, was taken hostage and died far from his homelands as prisoner in the west. His successor was unable to govern the paralyzed state of the south, and the Qin general Sima Cuo 司馬錯 attacked Chu from the Sichuan Basin that Qin had occupied some decades earlier. Two years later, general Bai Qi 白起 took the capital of Chu, Ying 郢 (modern Jiangling 江陵, Hubei) and advanced further to Lake Dongting 洞庭湖. King Qingxiang of Chu 楚頃襄王 (r. 298-263) fled to Chen 陳. The occupied territories were transformed into commanderies (jun 郡) as part of the state of Qin.

The last rulers of the Zhou dynasty

The last king of the Zhou dynasty was King Nan 周赧王 (r. 315-256), a grandson of King Xian. Nan is not his posthumous title but a kind of cognomen, like "the Timid" or "the Dishonourable". He is sometimes also referred to as "Lord of Zhou" 周君, or simply "the king". The "Bamboo Annals" (Zhushu jinian 竹書紀年) call him King Yin 隱王 "the Beclouded". The son of Duke Hui of Western Zhou, Duke Wu 西周武公, was uncertain whom of his sons to name as heir apparent. His righteous son, Prince Gong 共, had died prematurely. Sima Jian 司馬翦, an advisor to the king of Chu, was able to persuade Duke Hui to nominate Prince Jiu 咎 heir apparent.

In 307, the state of Qin attacked the town of Yiyang 宜陽, part of the territory of West Zhou. As a protective power, Chu supported the small kingdom of Zhou, yet planned to encroach on royal territory itself because Zhou had formerly been very generous towards Qin. The coalition advisor Su Dai 蘇代, brother of the famous Su Qin, convinced the king of Chu that it was of no use to punish the weak king of Zhou for the ancient alliance of Zhou and Qin and that it would be more profitable to become the political partner of the king of Zhou.

On another occasion the king of Qin planned an attack on the state of Han by marching just through the passage between Eastern and Western Zhou. Clerk Yan 史厭 explained to the king of Zhou that it would be of advantage if Han would cede some territory to Zhou and Zhou send some hostages to Chu. Qin would then suspect the state of Chu to plan an attack on Qin during its campaign against Han. At the same time King Nan should, as Yan suggested, explain to the king of Qin that Han suspected Zhou of conspiring with Qin because of the present of land made to Zhou. With this method the king of Zhou would increase his territory and avoid Qin troops marching through his land. The king of Qin, powerful as he was, summoned King Nan to his court to debate the question of attacking the city of Nanyang 南陽 in the territory of Han. A conspiration helped the two states to avoid a military conflict with Qin, by impeding the king to leave his home state.

Yet war broke out between East and West Zhou. The state of Han this time desired to support West Zhou, yet the king of Han was convinced not to support West Zhou, but instead to loot the ancient treasuries of the royal capital, where the Duke of West Zhou resided. At the same time Han came not into conflict with the problem of attacking the Son of Heaven, King Nan.

A few years later the state of Chu besieged the town of Yongshi 雍氏. Su Dai was able to involve the state of Qin into the conflict, so that the troops of Chu withdrew in fear of an attack by Qin.

In 281, the states of Han and Wei were already severely endangered by the military machine of the state of Qin. Su Li 蘇厲, another brother of Su Qin, suggested to the king of Zhou to negotiate directly with the infamous Qin general Bai Qi. With the parable of the archer Yang Youji 養由基, who hit his target each time he shot, it was suggested to Bai Qi that one single failure would ruin all his fame. Instead of attacking the state of Wei or the territory of Zhou, he was consulted to offer retirement because of illness. The chronicles do not say whether Bai Qi was really convinced by this arguments or not.

In 273, Ma Fan 馬犯 developed a plan to protect the famous nine tripods representing royal authority with the help of the king of Wei, who was also persuaded to construct a fortification wall for Zhou. A last time the king of Qin was convinced not to conquer the territory of Zhou. Prince Xu (sic!) 聚 (also written 最) explained that the annihilation of the land of the Son of Heaven would damage the reputation of Qin. Zhou even used to function as a spy for Qin in explaining the military changes in the state of Han, Wei and Zhao.

Only when Qin occupied the town of Fushu 負黍, belonging to Han, but in the vicinity of the ancient royal capital, King Nan decided to join an alliance against Qin. The Qin general (Prince?) Jiu 摎 charged the royal seat and forced the Duke of West Zhou to travel to the court of Qin, where he officially declared his submission and presented his whole territory to the king of Qin. The Duke was allowed to return.

With the death of the Duke of West Zhou and King Nan, ruler of East Zhou, in 256, the people of Zhou became "orphaned". Qin invaded the territory of West Zhou, seized the nine tripods and exiled the heir of West Zhou, Duke Wen 西周文公, to Da(n)hu in 𢠸狐. Seven years later the territory of East Zhou was occupied, and the house of Zhou was extinguished. The title of "Son of Heaven" was adopted by the king of Qin in 221, when he proclaimed himself the First Emperor 秦始皇帝 (r. 246-210 BCE).