I've had a long time to think these 20 years, and it's my opinion that the only way of defeating them is by joining all Shaolin styles into one combined technique.
12 seconds sound clip from the Mysterious Footworks of Kung Fu movie soundboard.
You can hear this line at 01:23:01.444 in the Blu-ray version of the movie.
Quote context
[...]
- At that time, the Shrimp and the Crab were the champions, fighting for the Emperor.
- Many revolutionaries have died at their hands. They're dangerous men. So I...
- Since then, they have never been defeated.
- Master, why haven't ya done it?
- I can't. I'm too old. And my broken legs can no longer stand it. It's too late.
- I'll perfect your style, just wait and see.
- You're too slow. You have to be faster.
- Master!
- Huh?
- Right.
[...]