Could be that the bolster needs to be ground down. Put the Wusthoff edge down on the cutting board with the heel (bolster) down. Can you see daylight between the edge and the board? If you sharpen it enough, the edge moves up the blade, but the bolster doesn’t, so there’s a gap between the edge and the board because the bolster is hitting the board and the edge isn’t. Red is bolster I’m talking about. Yellow is the edge. (This knife doesn’t have the problem I’m describing). Japanese knives don’t have these bolsters. Also, if you want a Santoku, then that’s what you should get!