Yan was a major state during the Spring and Autumn Period, but it was conquered by Qin in 222 BCE.

Qin was the first state to adopt Legalism as its official ideology in the 4th century BCE.

Chu was the last state to be conquered by Qin in 223 BCE.

Mencius was the most important Confucian philosopher during the Warring States Period. He was a student of Zisi, the grandson of Confucius.

Zhuangzi was the most important Daoist philosopher during the Warring States Period. He was a student of Liezi.

Han Fei Zi was the most important Legalist philosopher during the Warring States Period. He was a student of Xunzi.

Sun Tzu was the most important military strategist during the Warring States Period. He was the author of The Art of War.

The crossbow was the most important technological innovation during the Warring States Period. It was a powerful and accurate weapon that revolutionized warfare.

The Analects of Confucius is the most important cultural achievement during the Warring States Period. It is a collection of sayings and teachings of Confucius.

The Battle of Changping was the most important political event during the Warring States Period. It was a decisive victory for Qin over Zhao, and it paved the way for Qin's eventual unification of China.

The growth of trade was the most important economic event during the Warring States Period. It led to increased prosperity and economic development.

The rise of the merchant class was the most important social event during the Warring States Period. It led to increased social mobility and economic opportunity.

The growth of Confucianism was the most important cultural event during the Warring States Period. It led to the development of a new moral and ethical code for Chinese society.

The development of Confucianism was the most important philosophical event during the Warring States Period. It led to the development of a new moral and ethical code for Chinese society.

The development of Chinese mathematics was the most important scientific event during the Warring States Period. It led to the development of new mathematical techniques and concepts.