Qin dynasty
Note: King Zhaoxiang of Qin (秦昭襄王) had already been ruling Qin for 51 years when Qin annihilated the Zhou dynasty; however the other six warring states were still independent regimes. Some Chinese historiographers thus used the next year (the 52nd year of King Zhaoxiang of Qin) as the official succession from the Zhou dynasty.
Qin (state)
In the middle of the 3rd century , Zheng Guo, a hydraulic engineer from the Han state, was sent to Qin to advise King Zhaoxiang of Qin on constructing irrigation canals. Qin had a penchant for building large-scale canals, as evident from its Min River irrigation system. King Zhaoxiang approved Zheng Guo's idea on constructing an even bigger canal. The project was completed in 264  and the canal was named after Zheng. Qin benefitted from the project as it became one of the most fertile states in China due to the good irrigation system, and also because it could now raise more troops as a consequence of increased agricultural yield.