I've never read the wuxia novel itself so I cannot comment on the actual novel or how closely each adaptation follows the novel itself. However, I would like to share my thoughts, likes and dislikes on the adaptations I've had a chance to see watch over the years.
As a point of comparison, below are the adaptions I've watched :
Kung Fu Cult Master film starring Jet Li, Sharla Cheung and Gigi Lai
1986 TV series, starring Tony Leung, Kitty Lai and Sheren Tang
1994 TV series, starring Steve Ma, Cecilia Yip and Kathy Chow
2000 TV series, starring Lawrence Ng, Gigi Lai and Charmaine Sheh
2003 TV series, starring Alec Su, Alyssia Chia and Gao Yuan Yuan
2009 TV series, starring Deng Chao, Ady An and Liu Jing
It is very hard to really pick one favourite from all the above. I will say however that I found the film adaptation to be ridiculous, the 1994 TV series excruciatingly slow and the 2003 TV series to be merely watchable. Given a choice, I would have preferred not to have seen the film or the 1994 TV series adaptation. As for the rest, well here's how it is :
My favourite Zhang Wu Ji is by Tony Leung. The right balance of seriousness, strength and believable haplessness.
My favourite Zhao Min is by Gigi Lai. Her Zhao Min was truly unique. The cool type who doesn't leave people in doubt as to where her heart lies.
My favourite Zhou Zhi Ruo is by Sheren Tang. The change from her earlier sweet to ruthless and final repentance was the most believable.
My favourite Zhang Wu Ji and Zhao Min couple is by Deng Chao and Ady An. Both of whom run a close second to my favourite Zhang Wu Ji and Zhao Min. They bring a nice touch of playfulness and romance whenever they appear together in the 2009 TV series. The best parts of the 2009 series almost always involves the both of them together.
The 2000 TV series version has the best pacing however, excusing the rather strange ending with regards to Zhou Zhi Ruo and Song Qing Shu. With the other versions, even the ones I enjoyed like the 1986 and 2009 TV series adaptations, there were large sections that were rather slow. For example the sequences involving Zhang Wu Ji's parents abduction up until his discovery of the Nine Yang Manual tend to become rather boring and maudlin in almost all of the TV adaptations. The 2000 TV series has however escaped this fate.
As for the fight sequences, that would be too hard to decide. The 1986, 2000 and 2009 adaptations each had their own pluses. My current favourite would be my most recent watch which is the 2009 version.
My overall favourite would be the 2000 TV series version. It had pacing, my favourite Zhao Min and exciting fight sequences. The only real complain would be the conclusion of the story. I enjoy happy endings but it does not seem right or deserving for Zhou Zhi Ruo and Song Qing Shu to get one.
Heaven Sword and Dragon Sabre Originally published in Shvoong: http://www.shvoong.com/entertainment/tv/1999167-heaven-sword-dragon-sabre/
