Zai is the Mandarin pinyin romanization of the Chinese surname written 宰 in Chinese character. It is romanized Tsai in Wade–Giles. Zai is listed 302nd in the Song dynasty classic text Hundred Family Surnames. It is not among the 300 most common surnames in China. It was also confirmed not to be among the 400 most common surnames in 2013. Source: Wikipedia (en)