One of the subplots concerning Yeung Siu in HEAVEN SWORD & DRAGON SABRE is that he was in the process of writing or had written a history of the Ming Cult from its origins to Yeung Siu's own time. Undoubtedly, while compiling this history book, Yeung Siu learned about the incident between the Ming Cult and Wong Seung that occurred during the waning years of the Northern Sung Dynasty, over 200 years before Yeung Siu's own time.
When it was discovered late in HSDS that Ngor Mei Sect Leader Chow Chi Yerk was using the martial art 9 Yum White Bone Claws, the 9 Yum Jen Ging had already been missing from the martial world for a century since the death of Gwok Jing and Wong Yung at Seung Yeung Fortress. It was likely a surprise for everyone that this legendary martial arts manual still existed, but I would have been very interested in Yeung Siu's reaction to this revelation: he would have likely been very intrigued by the re-emergence of this martial art that Wong Seung had used to decimate the Ming Cult centuries earlier.