He retreated to deep into the mountain and built a thatch hut, he didn’t leave it
for three years, studying a way to break the skills of the [Jade Heart Manual], although there were a few successes, he wasn’t able to develop a complete [innerPower and techniques] set of skills to counter it. He was down heartened, and respected Lin Chao Ying’s intelligence even more, he admitted defeat and stopped researching.
[...]
His martial arts at that time was the world’s greatest,
the skills in the [Nine Yin Manual] were all profound and refined, after a glance and pondering for ten days, he understood [the essence of 9Yin], he laughed out loud to the sky, and returned to the tomb, and left the main aspects of the [Nine Yin Manual] on the ceiling in the most hidden room in the tomb, and the stances that would defeat the [Jade Heart Manual’s]. (Aside: recall that WCY "cannot" develop a "complete system" to defeat JadeHeartManual, and now he "could."
[...]
As a result of this conversation, the two lived in the valley for over another year.
The two went back into the tomb via the secret passage, and learnt the text of the [Nine Yin Manual]. When they were sure they remembered every single word, they left and practised outside. Within the year, the two’s internal and external skills improved in every aspect. But the markings that was left in the tomb by Wong Chong Yang were only parts which could defeat the [Jade Heart Manual] and consisted only a small part of the [Nine Yin Manual], comparing with what they know and what Guo Jing and Huang Rong knew, it was much inferior, but now, they weren’t the only two that knew it.
[...]
Even since the second mount Wah competition, Hong Qi Gong has not seen Ou Yang Feng for over then years.
Although Ou Yang Feng’s mind was unclear, he practised the [Contrary Nine Yin Manual], the more he practised the stranger his kung fu became, the stranger it became the more powerful he became.
Guo Jing and Huang Rong had recited a small portion of the manual to Hong Qi Gong, it made an impression on his kung fu and made great progress in his martial arts. The final stage ["final stage"] of the [Nine Yin Manual] is superior to the [Contrary Nine Yin Manual], although Hong Qi Gong only knew a little, he wasn’t inferior to Ou Yang Feng.
[...]
After tens of stances later, Yang Guo saw that the two’s incomparable swift and powerful attacks were turned from danger into safety,
he [YG] soon forgot about the safety of the two and concentrated on watching the mastery kung fu that was on display. The [Nine Yin Manual] is at the peak of the world’s martial arts, he only knew odd fragments of it, now he saw the two use the theories of the manual with their stances he couldn’t stop himself from being shocked and surprised, he thought, “So even an ordinary sentence of the manual has so many ways to express it.”