Jin Yong was not a science fiction writer, but perhaps the science fiction concept of parallel worlds...or a multiverse....might help to explain a few continuity discrepancies among his novels, especially between DEMIGODS & SEMIDEVILS and the CONDOR HEROES TRILOGY versus DEMIGODS & SEMIDEVILS and STATE OF DIVINITY.
A straight reading of Jin Yong's continuity begins with DGSD during the Northern Sung Dynasty, proceeds through the Southern Sung Dynasty with LEGEND OF THE CONDOR HEROES and RETURN OF THE CONDOR HEROES, moves forward to the Yuan Dynasty with HEAVEN SWORD & DRAGON SABRE, progresses into the Ming Dynasty with STATE OF DIVINITY and CRIMSON SABRE, and ends up in the Qing Dynasty with DUKE OF MT. DEER, FLYING FOX OF SNOWY MOUNTAIN, and BOOK & SWORD: GRATITUDE & REVENGE. Close readers of Jin Yong have noted, however, that there exist several significant discrepancies between DGSD's connection to the CONDOR HEROES TRILOGY and DGSD's connection to STATE OF DIVINITY. For example, many of the significant martial arts that appear in SOD are watered down or modified versions of martial arts that appeared in DGSD, but none of the CONDOR HEROES TRILOGY martial arts (or characters or events) were referenced in SOD. SOD often feels like it occurs in a shared universe with DGSD, but not with the CONDOR HEROES TRILOGY, which is illogical because the CONDOR HEROES TRILOGY is explicitly connected to DGSD as well.
It is illogical unless one accepts the theory of a multiverse.
DGSD being the earliest story in Jin Yong continuity (although one of the last to be written), it is the root of that continuity. I propose, however, that sometime after the end of DGSD, the Jin Yong timeline split into two divergent branches: one branch led into the CONDOR HEROES TRILOGY, and the other branch proceeded through the Southern Sung Dynasty (possibly WITHOUT the events of the CONDOR HEROES TRILOGY), Yuan Dynasty, and Ming Dynasty into SOD.
The point of divergence is most likely the life and career of Dook Goo Kau Bai, which post-dated DGSD and pre-dated the CONDOR HEROES TRILOGY. Dook Goo Kau Bai is the turning point because he is the only point of reference (other than the existence of the Mo Dong Sect and the Ngor Mei Sect in SOD, which might not necessarily be descended from the Mo Dong Sect and Ngor Mei Sect of HSDS because there was no explicit reference to HSDS Mo Dong and Ngor Mei characters or events in SOD) shared by SOD and the CONDOR HEROES TRILOGY. The Dook Goo Kau Bai referenced in SOD practiced Dook Goo 9 Swords, but might or might not have practiced the Heavy Iron Sword Technique. The Dook Goo Kau Bai referenced in ROCH practiced the Heavy Iron Sword Technique, but might or might not have practiced Dook Goo 9 Swords. Thus, using the multiverse model, during Dook Goo Kau Bai's life and career, the Jin Yong world split into two timelines:
Jin Yong Earth-1 became the world of THE CONDOR HEROES TRILOGY. Hong Lung 18 Palms, Dog Beating Stick Technique, and 1 Yeung Finger Technique survived from DGSD into this world, but the Siu Yiu Sect martial arts and Shaolin's Yik Gun Ging did not. JY Earth-1 developed such martial arts systems as the Heavy Iron Sword Technique, the 9 Yum Jen Ging, the 9 Yeung Jen Ging, the Keen Kwun Dai Loi Yee, Cheun Jen Sect martial arts, Ancient Tomb Sect martial arts, Peach Blossom Island martial arts, and White Camel Mountain martial arts. Qwai Fa Bo Deen, however, did *not* develop on JY Earth-1. Instead, it developed on JY Earth-2...the world where STATE OF DIVINITY occurred.
On JY Earth-2, the Siu Yiu Sect martial arts and Shaolin's Yik Gun Ging survived into the Ming Dynasty, albeit highly modified, and instead of the Heavy Iron Sword Technique being discovered by Yeung Gor during the Southern Sung Dynasty, Dook Goo 9 Swords was discovered by Fung Ching Yeung during the Ming Dynasty. On Jin Yong Earth-2, the fates of Hong Lung 18 Palms, Dog Beating Stick Technique, and 1 Yeung Finger Technique after DGSD were unknown, and other CONDOR HEROES TRILOGY martial arts such as the 9 Yum Jen Ging, the 9 Yeung Jen Ging, and the martial arts of the Greats and the Ming Cult never existed. In their place were the Qwai Fa Bo Deen and the Pik Che Sword Technique.
Interestingly, the divergent timelines come back together during the Qing Dynasty, because in DOMD, there are references to both the CONDOR HEROES TRILOGY (West Poison Au Yeung Fung's corpse-dissolving acid) and SOD (Ling Wu Chung was mentioned as one of Wai Siu Bo's childhood heroes).
Jin Yong likely didn't think about any of these things at all, and it's certainly not canon, but the multiverse model is an interesting way to look at a few continuity discrepancies in the Jin Yong world.