The Jiuyang Zhenjing, also known as the Nine Yang Manual, is a fictional martial arts manual in Jin Yong's Condor Trilogy. It was first introduced briefly at the end of the second novel The Return of the Condor Heroes. It plays a significant role in the third novel The Heaven Sword and Dragon Saber after Zhang Wuji discovers it and masters the skills in the book.
Read more about Jiuyang Zhenjing: Origin, The Return of The Condor Heroes