During the Qianlong period, Su Yanqing, the Lianghuai salt transport envoy, went to Yangzhou and discovered that the anti-counterfeiting code of salt introduction had been mastered by private salt lords. He kept his cool and created an original "silver wire secret mark" hidden on the edge of the new salt guide, using it as bait to wait for the big fish. In March, darknets emerged in seven provinces, and a silent battle involving national interests and private interests quietly unfolded in the salt affairs mystery. Su Yanqing used silver wire as a sword and vowed to kill the salt owl and cleanse the world.
