시영
The novel depicts Chai Jin as handsome-looking with eyebrows like those of a dragon, eyes like those of a fenghuang, red lips and white teeth. He is descended from Chai Rong, the second emperor of the short-lived Later Zhou dynasty. The Later Zhou general Zhao Kuangyin usurped the imperial throne from Chai Rong's young son, Chai Zongxun, in the Coup at Chen Bridge of 960 AD and became the founding emperor of the Song dynasty. According to "Water Margin", Zhao Kuangyin felt guilty about the usurpation so he treated the Chai clan well, granting them many privileges which were later passed on to their descendants. Among these was immunity from prosecution except for capital crimes. The privilege was inscribed in a "danshu tiequan" (丹書鐵券; literally, "iron certificate inked in red"). Chai Jin inherits his ancestors' residence in Cangzhou, Hebei, and the "danshu tiequan."