For comparison purposes I just received a Spyderco PM2 and out of the box the knife is scary sharp. Comparing it to my ZT 0920 the ZT is dull. The only sharpening tool I have is a Sharpmaker, which I have tried to sharpen the 0920 with. Yest it gets a little sharper, but is no where close to the PM2. I think I need to get a set of diamond rods and profile the ZT and then move through the medium, fine and ultra-fine rods. It appears the edge angle of the ZT is greater than 22 degrees or very close and I am using the 20 degree slots on the Sharpmaker. There doesn't seem that there is much steel moved on the ZT with the medium rod. I live overseas, SE Asia, and sending it back to ZT would end up costing 30% of the price of a new knife.