Qi (齊/齐, also commonly written as Ch’i in Wade–Giles, and Chai (Jyutping: cai4) in Cantonese) is a Chinese surname originated from the Qi (state) (齊/齐).
In 2013 it was the 113th most common name, shared by 1,760,000 people or 0.130% of the population, with the province with the most being Hebei.
[1] It is the 87th name on the Hundred Family Surnames poem.