|Water Margin character|
|Also known as||
|Rank||10th, Noble Star (天貴星) of the 36 Heavenly Spirits|
|Chief accountant of Liangshan|
|Origin||Nobleman, descendant of Chai Rong|
|First appearance||Chapter 9|
Chai Jin is a fictional character in the Water Margin, one of the Four Great Classical Novels of Chinese literature. He ranks 10th of the 36 Heavenly Spirits of the 108 Liangshan heroes and is nicknamed "Little Whirlwind". His role in the novel is straddled between an idling aristocrat who befriends jianghu figures and a maverick who toys with the status quo associated with his royal lineage.
The Water Margin describes Chai Jin as having eyebrows like those of a dragon's, eyes like a phoenix's, red lips and white teeth. His ancestor is Chai Rong, Emperor Shizong of the Later Zhou. During the Chenqiao Mutiny, Zhao Kuangyin's followers dressed him in an emperor's robe and urged him to take the throne of the weakening Later Zhou, to which Zhao agreed reluctantly. Zhao Kuangyin founded the Song Dynasty later and became Emperor Taizu of Song. However, Zhao Kuangyin felt guilty over seizing the Chai family's throne, so he treated the Chais well and bestowed them with a danshu tiequan (丹書鐵券; literally: iron certificate inscribed in red ink). Holders of danshu tiequans are seen as excluded from the jurisdiction of the government, as they are entitled to certain special privileges, such as being spared the death penalty for committing capital crimes. Chai Jin inherits his ancestors' residence and the danshu tiequan.
Some of the 108 outlaws, who were forced to become fugitives, often seek refuge in his residence before making their way to Liangshan Marsh. For example, Song Jiang once hid in Chai Jin's residence after killing Yan Poxi to evade arrest, since Chai's house is protected from the authorities by his danshu tiequan. Lin Chong also received financial aid from Chai Jin before and stayed in his residence temporarily after the burning of the fodder storage field. Wu Song also stayed in Chai Jin's residence after thinking that he had killed someone by accident. The outlaws regard Chai Jin as an ally and close friend.
Once, Chai Jin's uncle is bullied by Gao Lian's relative, Yin Tianxi, in Gaotangzhou (present-day Gaotang County). Chai Jin's uncle dies from his wounds caused by Yin Tianxi. Chai Jin confronts Yin Tianxi with Li Kui. Yin Tianxi behaves arrogantly and rudely towards Chai Jin and Li Kui kills Yin in anger. Gao Lian is furious and he has Chai Jin arrested and thrown into prison, showing complete disregard for Chai's danshu tiequan. Meanwhile, Li Kui escapes and he returns to Liangshan to seek help.
The Liangshan outlaws attack Gaotangzhou to rescue Chai Jin. Gao Lian uses dark magic and succeeds in holding off the outlaws until Gongsun Sheng arrives and defeats him in a battle of magic. Gaotangzhou is conquered by the outlaws and they enter the prison to search for Chai Jin. They are unable to find Chai Jin in the cells and eventually they learn from a warder that Gao Lian has hidden him at the bottom of a dry well. Chai Jin has been severely tortured by Gao Lian and is deprived of food and water and appears to be on the verge of dying. He is saved in time and provided with medical treatment and survives.
Becoming an outlaw
Chai Jin decides to join Liangshan as an outlaw. He becomes the chief accountant of Liangshan's income and provisions together with Li Ying. He follows the heroes on their campaigns against the Liao invaders and rebel forces after they have been granted amnesty by the emperor.
During the Fang La campaign, Chai Jin, along with Yan Qing, infiltrates Fang La's territory and as a mole for the Liangshan forces. Using the undercover identity of "Ke Yin" (柯引), Chai Jin manages to win the trust of Fang La and his generals, and becomes Fang's son-in-law after marrying Fang's daughter, Princess Jinzhi. During the last battle, Chai Jin provides Fang La's army with a false sense of security by defeating several Liangshan generals in battle, but in reality they were only feigning and no one was hurt. Fang La is caught off guard when Chai Jin and Yan Qing suddenly reveal their true identities and start attacking him. Fang La's nephew, Fang Jie, is killed by the combined efforts of Chai Jin and Yan Qing in the battle and the heroes eventually capture Fang La's final base with Chai's help.
Chai Jin is one of the few survivors after the campaigns and is given an official post by the emperor in recognition of his contributions. Fearing a possible retaliation by the treacherous ministers for becoming a prince consort in Fang La's royal family earlier, Chai Jin later resigns from his post and returns home. He leads a happy and luxurious life until the end of his days.
- List of Water Margin minor characters#Chai Jin's story for a list of supporting minor characters from Chai Jin's story.
- (Chinese) Li, Mengxia. 108 Heroes from the Water Margin, page 21. EPB Publishers Pte Ltd, 1992. ISBN 9971-0-0252-3.
- Buck, Pearl. All Men are Brothers. Moyer Bell Ltd, 2006. ISBN 9781559213035.
- Zhang, Lin Ching. Biographies of Characters in Water Margin. Writers Publishing House, 2009. ISBN 978-7506344784.
- Shibusawa, Kou. Bandit Kings of Ancient China, page 92. KOEI, 1989.
- (Japanese) Ichisada, Miyazaki. Suikoden: Kyoko no naka no Shijitsu. Chuo Koronsha, 1993. ISBN 978-4122020559.
- Miyamotois, Yoko. Water Margin: Chinese Robin Hood and His Bandits.
- Keffer, David. Outlaws of the Marsh.