Yao-xian Zheng first received a task from Dai Li, and went to Yan 'an to meet the shadow. He originally thought that the contact person was Wang San, but Wang San just said that he was carrying out the task taught by the shadow. Zheng Yaoxian concluded from Wang San's words that the shadow was still in Yan 'an.

Later, Zheng Yaoxian learned from Dai Li that the shadow could contact the mountain city by telegraph. At that time, the telegrams in Yan 'an could only be contacted by the public security bureau and other relevant security departments. Jiang is the deputy director of the Public Security Bureau, so Zheng Yaoxian is suspected.

Zheng Yaoxian's direct proof that Jiang is a shadow is Yuan Nong's Kite Story in Anger. Yuan Nong has always wanted to know about kites. He asked Lu Hanqing more than once, and also asked Jiang, the deputy political commissar working in Yan 'an. This sentence made Zheng Yaoxian suddenly feel that kite is a very secret secret, but the message he brought back from Yan' an was that "kite is hidden at the highest level of the military system."

According to the above clues, Zheng Yaoxian finally judged that ginger was the shadow.