If I'm not mistaken, the "pointer finger" is a cary-over from traditional single bevel technique and the tip of the finger partially raps over the edge of the spine so it lines the blade up with the arm and keeps the wrist straighter,thus adding more control and precision.... Also keep the finger tips from wandering too low on short heeled knives. I'd never see it used when chopping though.
I was also amazed that this guy still has knuckles left, but I think what he's doing is bringing spine of his knife up into the underside(front overhang) of his knuckles.
This is instead of rubbing the side of the blade against the top of the knuckles like you can with a taller blade.
Any guesses on the knife makes?
I'd love to see some more video/explanation from a suji pro. Maybe Jon will dust off the ol' line cook skills?