Sword Stained with Royal Blood is a wuxia novel by Jin Yong (Louis Cha). It was first serialised in the Hong Kong Commercial Daily between 1 January 1956 and 31 December 1956. The book has three editions. Some characters from the novel play minor roles in The Deer and the Cauldron, another novel also by Jin Yong, and the plots of both novels exhibit certain connections.
Set in the late Ming dynasty, the story centers on Yuan Chengzhi, the son of Yuan Chonghuan, a patriotic military commander who was wrongly put to death by the Chongzhen Emperor. An orphan, Yuan Chengzhi is sent to the Mount Hua Sect, where he is tutored in martial arts by Mu Renqing. He grows up to become a fine young martial artist and he leaves Mount Hua in search of adventure. Serendipitous incidents lead him to discover the Golden Serpent Sword and a martial arts manual, which once belonged to Xia Xueyi, a long dead enigmatic swordsman. Yuan Chengzhi inherits Xia Xueyi's possessions and skills and he becomes more powerful than before.
Yuan Chengzhi wanders around the land and meets Wen Qingqing, a young maiden from a family of brigands. Wen Qingqing is actually Xia Xueyi's daughter and she follows Yuan Chengzhi after being expelled from her family. Yuan Chengzhi initially wanted to seek redress for his father, but decides to join Li Zicheng's rebel army to overthrow the corrupt Ming government. He helps the rebels retrieve the gold robbed by the Wen family, sabotages a battery of cannons supplied to the Ming army by foreigners, and finances the rebellion with part of the treasure he discovered in Nanjing. Yuan Chengzhi also befriends several jianghu martial artists, who pledge allegiance to him out of respect for his heroism. Yuan Chengzhi organises his followers to form an army and they pledge to serve and defend China from invading Manchu forces in the northeast.
Eager to prove his loyalty to his countrymen, Yuan Chengzhi infiltrates the Manchu capital Mukden and attempts to assassinate the Manchu ruler Hong Taiji but fails. Later, despite harbouring a grudge against the Chongzhen Emperor for his father's death, he saves the emperor from a coup led by a treacherous noble called Prince Hui. During that time, he meets He Tieshou, one of Prince Hui's allies and the leader of the Five Poisons Cult. Yuan Chengzhi succeeds in reforming her and accepts her as his student. He also develops romantic relationships with Wen Qingqing and a maiden called A'jiu, who is actually the Chongzhen Emperor's daughter Princess Changping.
Yuan Chengzhi's decision to support Li Zicheng eventually makes him regret, because after overthrowing the Ming government, Li not only fails to fulfil his promises to restore peace and stability, but also condones his followers' brutality towards the common people. Yuan Chengzhi is disappointed with Li Zicheng and decides to leave. A former Ming general called Wu Sangui later defects to the Manchus and allow them to pass through Shanhai Pass and overrun the rest of China. When Yuan Chengzhi learns that China has fallen to the Manchus, he realises that he is unable to do anything to reverse the situation and decides to leave for good and he sails to a distant land with his companions.