To answer David's question. Yes, that is what I first thought. Mostly. I also remember thinking "Jesus, he's strong. How come he doesn't look a lot bigger than me?" Of course, that has to do with why the impression described by the first sentence is wrong. It's as much about developing "feel" and balance, and the application of leverage, as it is learning technique. Oh, and muscle response, or memory, whatever you want to call it. Yeah, it's a lot of stuff.
I got beat down by an All American wrestler, my size, for months. It was actually judo back then, not jits, and he was on his off- season helping his wrestling coach teach a one hour college phys ed class. I was a little, pot bellied, bottom of the barrel evening grocery department manager. We would do judo for real after the class was over. Oh, man! That was six months of Hell! So sore I couldn't move after practice. Blisters on the top of my feet. Fingernails all wripped off.
And then I choked him out with a standing lapel double fist choke that I learned from some book. I can still remember the little gasp he made when I put on the squeeze. And then he fell into me, so I thought he was fighting it, and I kept squeezing. And then I figured out that he was just dead weight, so I let him slide to the floor and woke him up like he had woke me up, a time, or two. First submission, Baby!
Fucking magic, fucking magic, fucking magic. ... Holy God! That was 24 years ago. Sheit! It's still better than sex ... most of the time. : )