Pai Mei invincible a part from certain times of day?

[Omni Dragon]

Before I saw EXECUTIONERS FROM SHAOLIN I listen to Bey on a cometary for one of the Tai Seng KUNG MASTER TV series DVDs & IIRC he said that Pai Mei invincible a part from certain times of day now that made be think Pai Mei was the ultimate villain ever if you follow the idea of for a villain to great challenge for the hero to over come the villain has to be more powerful than the hero can possibly imagine & seem the almost impossible task & being invincible would mean impossible for the hero to beat but if the villain was invincible most of the time then the is a very slight possibly of beating him then.

I don't think the film actually say it he's invincible a part from certain times of day but it could be interpret as that.

Here's the subs:

& the dub says it pretty similarly though it says "only then can you kill him" at the end

IMO I think its most probably means that Hung Hsi Kuan(Chen Kuan Tai) would never be powerful enough to kill Pai Mei(Lo Lieh) a part at "between 1 p.m.to 3 p.m."

Or maybe less likely Pai Mei is invincible a part from "between 1 p.m.to 3 p.m." & can not be killed another time.

I know this is probably a silly post that I may have answered myself by saying what I think is the most probable answers but I like to know your opinions? As it has been bothering be for a while.

[odioustrident]

I thought this had something to do with his chi flow being weakest at the point furthest from sunrise and sunset. I have no idea where I got this notion; it may be from another film.