The knife in question is a Masamoto Honyaki Sujihiki, manufactured by a Japanese Masamoto Sohonten Company, which has been around since 1872. Masamoto knives are some of the best in the world; each one is inspected by top Japanese sharpener Mr. Shouzou Mizuyama. The knives range in price from about $100 to $3,000 and can be purchased through Korin. But once you have a good knife, even a great knife, the real trick is keeping it sharp. There is an entire world of chef forums, essays, and YouTube videos dedicated to that topic. BuzzFeed Food will tackle it soon enough.