Which skill is the best?
* Yoga: could increase inner energy of the practitioner quickly, help him/her to be able to absorb different poisons and different medicines to increase his/her inner energy. Besides, the time of mastering this skill was not long as well. YTZ mastered this skill in less than 1 year.
* 9 Yang: balanced Yin and Yang, could increase inner energy of the practitioner quickly, heal his/her and others' internal diseases, absorb opponent's energy, make up auto-shield, expel poisons, abolish opponent's Yin energy. Required time: at least 5 years.
* 9 Yin inner energy method: was an extreme Yin skill, could restore the lost energy of the practitioner and his/her lost Kung Fu. Required time: 15 - 20 years.
* Yi Jin Jing: could merge different inner energy streams, help practitioner's energy not to be absorbed by opponent's skills. Required time: not mentioned in JY's novels.
I chose 9 Yang.