It was difficult to have a definite answer as to who was the number one expert in Jin Yong's martial arts world because every expert had their own unique characteristics and strength. However, if we only consider the characters that appeared in Jin Yong's novels, the following are some of the characters that might be considered the number one experts: 1 Duan Yu: Duan Yu is the son of the Emperor of Dali. He has peerless martial arts and is known as a genius in the martial arts world. He was very powerful and had extraordinary martial arts and martial arts skills. 2 Xuzhu: Xuzhu is a disciple of Wuyazi. He doesn't have any actual martial arts, but his comprehension is extremely high and he has a kind heart. Therefore, he is known as the "number one expert in the martial arts world". 3 Duan Zhengchun: Duan Zhengchun was the Emperor of Dali. He had extremely powerful martial arts and wealth, and was known as the richest man in the martial arts world. 4. Qiao Feng: Qiao Feng is a famous martial arts master in Jianghu. He has excellent martial arts and combat skills and is one of the most righteous characters in Jin Yong's novels. 5. Linghu Chong: Linghu Chong is the eldest disciple of the Huashan Sect. His martial arts are strong and he has an open-minded heart, so he is known as the "number one master in the martial arts world". It should be noted that these characters were very powerful and were described to different degrees in different novels. Therefore, this answer was only for reference.