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.
Ziying
Ziying (died January 206  BC) was the third and last ruler of the Qin dynasty. He ruled over a fragmented Qin Empire for 46 days from mid-October to early December in 207  BC. He is referred to in some sources with the posthumous name Emperor Shang of Qin (秦殤帝), despite Qin abolishing the practice of posthumous names. (In Chinese tradition, even someone who never held a ruling title while alive might be given the posthumous title "emperor" after his death.)