Chen Tuan (871-989) was a legendary Daoist sage. His birth name was Chen Tuan (陳摶); his other name was Tunan (圖南). He was posthumously named Xī Yí (希夷) by the emperor. He was also called fondly as Fu Yao Zi (扶搖子).
Traditionally in China, a person’s birth name and his other name are closely related with the other name an annotation of the birth name. However, in Chen Tuan’s case, his birth name is actually intimately related to the name given by the emperor.
Let us take a look at Chapter 14 of the Dao De Jing 道德經：
Look without seeing is called Yi;
Listen without hearing is called Xi;
Touch without feeling is called Wei.
Chen Tuan’s birth name wants him to put everything into practice in order to understand. The emperor knew him too well to be a superb Daoist. Therefore, he gave him the name Xi Yi希夷 meaning he already reached the state described by Dao De Jing. He looks without seeing, listens without hearing and touches without feeling. It is this state that qualifies him to be a real Daoist.