I did not watch the whole 20 minute video. But I have to say I do not care at all for how he's holding the knife in the photo icon. His thumb is begging to get broken, and his grip is loose, with the blade coming out distal to the PIP joint. That's weak. In the bit of the video I watched, he holds the knife by making a fist, with the blade coming out between the 2nd and 3rd MCP joints. Much better.