I think "sharpest" may be a bit of an exaggeration in the title. While the technique is cool and I recommend watching more of this guy's videos, it's by no means the sharpest knife. I have a small business hand sharpening knifes using a similar technique (Japanese ceramic whetstones and hones) and I can easily make one much sharper within a few minutes. It's a great hobby and a good way to make some side cash if you learn your stuff.