Chiang Wan-an, born in 1978 in Taipei, Taiwan Province, China, is a Chinese Nationalist politician. As for the reason for his father's surname Zhang, it starts with his grandfather Chiang Ching-kuo.
Chiang Ching-kuo, the eldest son of Chiang Kai-shek, was sent to Ganzhou, Jiangxi Province in 1942 to preside over a training course for young cadres, where he met Zhang Yaruo, and the two soon fell in love and had twin sons, named Zhang Xiaoyan and Zhang Xiaoci. However, due to Zhang Yaruo's identity, Chiang Ching-kuo could not disclose their relationship, and the two children could only follow their mother's surname Zhang.
Zhang Yaruo died shortly after giving birth to the children, and the two children were sent by Chiang Ching-kuo to the home of his sworn brother Zhang Haoruo to be raised. During that particular period, their identities were not publicly acknowledged, and it was not until 2005 that Chang Xiaoyan officially changed his surname back to Chiang in Taipei and changed his name to Chiang Hsiao-yan.
Therefore, Jiang Wanan's father's surname is Zhang because his grandfather Jiang Jingguo and Zhang Yaruo fell in love and had twin sons, and due to special historical reasons, they could only follow their mother's surname Zhang. The story also reflects the special context of that era and the complex relationships of the family.