Anybody know when- or how- the gut wrench was invented as a wrestling move? I was watching matches from the 70's and they don't really gut wrench at all... then in the 80's they seem to be gut wrenching all over the place. Any wrestling historians care to explain?

Dziedzich vs Barzegar, 1977 world. The guys here use the waist lock to set up leg rides and throws, but not as modern gut wrench.

Tediashvilli vs Stottmeister. Teddy never even tries to gut wrench even though his opponent is way up off the ground. Also, Tediashvilli seems like an absolute killer.

And the 80's:
Schultz vs Nagashima

Lewis vs Akaishi- one of my favorite matches of all time.