I've recently noticed that I really f**king up the geometry of my most used knives (Yusuke 270 gyuto and 210 petty) through my sharpening technique, or lack thereof. When I got into sharpening a little over a year ago, I played with several different techniques, and settled on a full sweep from tip to heel along the entire length of the stone. Recently, however, I've done a couple of Jon's on-line seminars and I now using a traditional Japanese technique.
Somehow I'm putting pressure from the tip back about a few inches and the factory curve in the tip in being flattened out and it's starting to look like a bird's beak. I have an idea of how to go about making it look better by grinding off some of the area at the transition between the main belly and the tip.
What's happening can pretty easily been seen in the photos. The top photo is my 270 gyuto in itís current state. The middle photo is my 300 suji on top (which hasnít been sharpened much, hence it still has the original profile), middle is the gyuto, and bottom is my 210 suji which is starting to show signs of the same deformation. The bottom photo is my 270 gyuto when it was brand new.
I'd really love some feedback as to what I may be doing wrong and what to do to correct it. Cheers! mpp