Государство У в период Чуньцю и эпохи Чжоу

State during the Spring and Autumn period
the Zhou dynasty state

Wu (; Old Chinese: *) was a state during the Western Zhou dynasty and the Spring and Autumn period, outside the Zhou cultural sphere. It was also known as Gouwu (句吳 /*/) or Gongwu (工/攻吳 /*/) from the pronunciation of the local language. Wu was located at the mouth of the Yangtze River east of the State of Chu and south of the State of Qi. Its first capital was at Meili (梅里, in modern Wuxi), then Helü's City (闔閭, in present day Xueyan town near Wuxi), and later moved to Gusu (姑蘇, probably in modern Suzhou).

A founding myth of Wu, first recorded by Sima Qian in the Han dynasty, traced its royal lineage to Taibo, a relative of King Wen of Zhou. According to the Records of the Grand Historian, Taibo was the oldest son of Gugong Danfu and the elder uncle of King Wen who started the Zhou Dynasty. Gugong Danfu had three sons named Taibo, Zhongyong, and Jili. Taibo was the oldest of three brothers, Jili being the youngest. Realizing that his youngest brother, Jili, was favored by his father to inherit the throne of Predynastic Zhou, the older brothers Taibo and Zhongyong left Zhou to avoid conflict and settled southeast to Wu with a group of followers loyal to him and his brother Zhongyong. They established their first capital at Meili (梅里), believed to be today's Meicun in Wuxi. Taibo's youngest brother Jili who was eventually the heir of the throne became the father of King Wen, who is attributed to starting the Zhou dynasty. Little is known about the history of Wu before the Spring and Autumn period. Wu rose to power in the 6th century BC, after it was aided by the State of Jin as a useful ally against the State of Chu. In 584 BC, Wu rebelled against Chu upon the advice of Wuchen, a Jin minister, who defected from Chu. From then on, Wu would become a constant threat to the Chu Kingdom. Wu planted seeds of rebellion amongst Chu's vassals along the Yangtze valley. Wu Zixu, a highly influential Chu politician's mother and brother was murdered by King Ping of Chu and fled to Wu plotting revenge. Wu Zixu later became a trusted advisor of Prince Guang and helped him assassinate his cousin King Liao of Wu and usurp the throne. After the successful assassination of King Liao, Prince Guang ascended the throne and became known as King Helü of Wu. In 506 BC, during the reign of King Zhao of Chu, King Helü decided to invade Chu. The king personally led the army, along with his younger brother Fugai, Wu Zixu, as well as Sun Tzu, author of The Art of War. Although Chu had a strong army led by Nang Wa and Shen Yinshu, it suffered a heavy defeat at the Battle of Boju. King Zhao of Chu fled to Sui and the Wu army captured Ying, Chu's capital. After entering Ying, Wu Zixu exhumed King Ping's corpse, and gave it 300 lashes to exact vengeance on for his mother and brother who were murdered by the Chu King. The last king of Wu, King Fuchai had at least four sons, three of whom were named You, Hong and Hui. You was his heir but was killed in one of the battles leading to the defeat of Wu, and Hong became the new heir. After the collapse of the state, the other three sons of Fuchai were exiled. Themselves, their blood relatives and descendants took Wu as their clan name in honor of their fallen kingdom.

The Records of the Grand Historian states that the people in Wu wore their hair short and sported tattoos. For Sima Qian this would have illustrated their supposed barbarism, as in his time Chinese men and women were not allowed to cut their hair or otherwise modify their body doing so was considered an offence against the ancestors from which one had inherited one's physical features. Wu rulers did not receive posthumous names after death.

The rulers of Wu are said to be descendants of early Zhou; however, the indigenous language of the Wu region is distinct from Old Chinese spoken by central Chinese states. Historians have attempted to link the language with Austronesian languages, Kra–Dai or a non Chinese Sino Tibetan language.

"Wu" continues to be used as a name for the region around Suzhou and Shanghai and their regional speech, Wu Chinese. It was employed by other states and princes holding power in the region, most notably Eastern Wu of the Three Kingdoms, and Wu and Wuyue of the Ten Kingdoms.

Ambassadorial visits to Japan by the later Chinese dynasties Wei and Jin recorded that the Wajin of Japan claimed to be descendants of Taibo of Wu, traditionally believed to be the mythical founder of Wu. Several scholars suggest that the Yamato people and the Imperial House of Japan are descendants of the Wu and possibly Taibo. Many Japanese historians also link the early Japanese Yayoi people to the Baiyue tribes.

Wu, together with Yue, is represented with the star Zeta Aquilae in asterism Left Wall, Heavenly Market enclosure (see Chinese constellations).