Ximen Bao (Chinese: 西門豹) was a government minister and court advisor to Marquis Wen of Wei (reigned 445–396 BC) during the Warring States period of ancient China. He was known as an early rationalist, who had the State of Wei abolish the inhumane practice of sacrificing people to the river god He Bo. Although the earlier statesman Sunshu Ao is credited as China's first hydraulic engineer (damming a river to create a large irrigation reservoir), Ximen Bao is nonetheless credited as the first engineer in China to create a large canal irrigation system.
Ximen Bao became well known in his lifetime and posthumously for his grandiose works in hydraulic engineering during the 5th century BC. He organized a massive diversion of the Zhang River, which had formerly flowed into the Yellow River River at Anyang. The new course that the river took under his diversion project brought the river to meet the Yellow River further down its course at a bend near modern-day Tianjin. The Zhang River rises in the mountains of Shanxi province, flowing southeastwards, and at the time added to the burden of overflow for the Yellow River. Ultimately though, the purpose of this enormous project of engineering was to irrigate a large agricultural region of Henei (in the left lower Yellow River basin) by providing it with a natural contour canal.
Work on the canal system began sometime between 403 BC and 387 BC, when Marquis Wen and his successor Marquis Wu reigned over the State of Wei. Due to several setbacks (including some temporary local resistance to corvee labor service) it was not fully completed until a century later, during the time of Wen's grandson, King Xiang (襄王) (r. 319–296 BC). It was during this time that the Wei engineer Shi Chi completed the work of Ximen Bao.
- Needham, Volume 4, Part 3, 271.
- Needham, Volume 4, Part 3, 371.
- Needham, Joseph (1986). Science and Civilization in China: Volume 4, Part 3. Taipei: Caves Books, Ltd.