West Poison Au Yeung Fung's memory problems did not become apparent until after he had defeated East Heretic Wong Yerk See and North Beggar Hung 7 Gung at the Second Mt. Hua Sword Tournament. He was a bit manic to be sure, but nothing seemed to indicate that he had truly lost his marbles until after the fight....when he began calling Gwok Jing "his son" (in reference to the slain Au Yeung Hak), calling Wong Yerk See "Prince Deun" (in reference to South Emperor 1 Deng, who wasn't even there), and forgetting his own name.
At what point did Au Yeung Fung actually snap, and what really caused his mental imbalance? Was it really his practice of the reverse 9 Yum Jen Ging (because he had already been doing that for about a year, but was still behaving more or less normally just an hour before the Second Mt. Hua Sword Tournament)? In a short skirmish against Hung 7 Gung not long before the actual tournament, Hung 7 Gung managed to land a blow directly on top of Au Yeung Fung's head while Au Yeung was confused by some nonsense verses that Wong Yung had uttered. Was it the strike by Hung 7 Gung that caused Au Yeung Fung's brain damage, or was it the reverse 9 Yum Jen Ging (or perhaps both factors)?
Finally, what brought Au Yeung Fung's sanity and memory back just before he died in ROCH?