I know that at 22 minutes this is a long video, but it sucked me in and I watched the whole thing. Walter Sorrells is a master teacher. I love his explanations at each step, and I like how he isn’t afraid to criticize his own work. The videography is top-notch as well. Check out his entire YouTube Channel.
In this video, Walter documents his first ever attempt to make a yanagi-ba bocho (literally “willow blade knife”). A yanagiba is the traditional sashimi-knife. It has a long, thin, chisel-ground blade, meant to cut translucent pieces of fish in a single pull-stroke.
Walter goes with a traditionawhere a hard Hitachi steel edge is forge welded to a piece of antique wrought-iron anchor chain.
In preparing sashimi and sushi, there are very important conditions that the sliced cross section be smooth, shiny and sharp in a microscopic view. Those conditions cannot be met by other usual knives. Yanagi-ba-bocho is especially designed to satisfy the conditions. Important design points for it are as follows:
- Length: It has a long blade to cut a fish block only in one direction (pulling). Zigzag cutting creates a bad cross section.
- Thickness: It has a very thin blade to allow cutting using very little force. Using greater force would result in tearing or smashing instead of cutting.
- Unstickiness: The back faces of some Japanese knives are scooped out to easily detach the sliced piece from the blade after cutting.
- Hardness and toughness: Consistency in durability and sharpness is created in the same way as a Japanese sword. The blade is formed from a combination of two different steels, a softer outer jacket of steel wrapped around an inner core of harder steel.
- Single ground: A yanagi-ba blade is angled only from one side, with the other side of the blade being flat. This allows control in the blade angle for delicate cutting and allows for ease of sharpening. The figures in this article are for right-handed version in which the blade is ground only on the right side (front face). Left-handed versions exist, but are relatively scarce and expensive.
- Cutting direction: While almost all western knives are used to push and cut, almost all Japanese knives are used pull and cut instead.