There must have been some special effects. Wouldn't be too difficult to fast forward the action and then use the faster version as the final cut.Shen Shengyi had some of the best swordfights ever choreographed on TV. I wonder who's the martial arts instructor and choreographer. I was too young then to bother about such things. But frankly, if you're able to get get a Shen Shengyi DVD and watch it again, I think you'd know what I mean. The swordfighting were swift and smooth and stunning without any hint of slow motion, fast motion or special effect. Shen Shengyi wore his sword loosely clipped at his waist without a sheath, classic. Instant strike anytime. It bypassed (not broke) the rules of even the best swords, i.e. out of sheath then must see blood. His sword got no sheath! Caveat emptor!
The swift swordplay and the sword without the sheath were both deliberate. Shen's forte was swift swordplay to defeat and kill his opponents, while the unsheathed sword was a symbol that he was ready to kill at anytime. He was not the typical hero, who only unsheathed his sword, when people were in need of help.
It would have been interesting to see a duel between Shen and Zhang Sanfeng's Taiji Jian. Fast vs Slow. Zhang would have used his opponent's speed against him.