Cài (Chinese:蔡) is a Chinese surname that derives from the name of the ancient Cai state. It is regionally more common in China's Fujian Province and in countries settled by ethnic Chinese from that province than in China as a whole. The surname is the 34th most common surname in China, but the 9th most common in ******, where it is usually romanized as Tsai, and the 8th most common in Singapore, where it is usually romanized as Chua, which is based on Hokkien pronunciation. It is also a common Cantonese name in Hong Kong where it is romanized as Choy, Choi or Tsoi, in Macao and Malaysia, it's spelled as Choi, in Malaysia and the Philippines as Chua, in Thailand as Chuo (ฉั่ว). Moreover, it is also romanized in Cambodia as either Chhay, Chhuor or Chhor among Chinese Cambodians.