Before you learn how to use the knife, you must learn and master knife sharpening using whetstones. At some Japanese restaurants, just like your knives, you are expected to have your own sets of Whetstones to avoid others altering their flat surface. Improper use and sharpening technique on a gliding stone will result in an uneven surface on the whetstone, which in turn, can make the blade uneven, wavy, curved and dull.
The Whetstones come in different grade -rough to shave off as much metal as you can, medium for toning and fine for the smooth finish. Each stone has a number like 1000 and 2000, where the higher the number is, the finer the stone is. The medium 1000 King Whetstone is what I used in the beginning because that was what they had at Rock N Hollywood Sushi. It looked exactly like a brick, a brown stone. You must first immerse in in water entirely to get it wet until the stone soaks up as much water as it can, then it becomes ready just the perfect hardness to place your knife for sharpening.
The sharpening technique is very simple – I can explain and show it to you in thirty seconds. You glide your knife, angling around 12 degrees or so on one side, flip it and do the dame on the other side. The trick is to keep the same angle, applying the same pressure and glide the knife same number of times on each side. For example, if you slide your knife ten times on one side, you do ten on the other side also.
The knife I was using was called Yanagiba, Willow Leaf Blade. Though many people think it’s a Sushi Knife, there is no such thing as Sushi Knife. Instead, Yanagiba is a Sashimi Knife. One of the most distinctive features of Yanagiba and Japanese Knife is that it is single beveled. Only one side is sharpened and the other side is flat. I always thought sharpening single beveled knife was easier than double beveled western knives because when sharpening a Japanese knife, I just lay it flat on one side, press it firmly and glide without worrying about keeping the same angle on both sides.
Toshi told me how to sharpen the knife. “You need to soak the stone in water until the bubbles stop floating up. The bubbles are the sign that the stone is still soaking water, not ready.”
When sharpening the knife, one thing to be careful of is to keep a firm grip on the knife and avoid slipping your fingers off the surface of the knife. If you are right-handed, you hold the handle with right hand, and place your left fingers on top of the knife blade, applying firm pressure and move the knife up and down. The most dangerous thing is when you slip your left fingers by accident as you move the knife forward/up with your right hand then, you cut your left finger with the knife. Because you are applying a good amount of pressure, if you cut your left fingers, there is a great chance of slicing through the skin off. Luckily, I have never sliced off my fingers as I sharpen my knives, but have cut my fingers and caused bleeding enough times to learn to be careful and attentive when sharpening my knife. When you work in a professional kitchen, there are a lot of chances of slicing your fingers. When you cut your fingers at the sushi bar during the restaurant business hours, it’s not really acceptable. However, they will forgive you as a mistake, so you tell yourself not to make the same mistake again. But, when you cut your fingers when sharpening your knife, it’s very denigrating and embarrassing, like a professional athlete injured his leg during offseason. No matter what, knife cuts at the sushi bar always felt distressing and embarrassing. The worst part is not so much of the pain or bleeding: it’s the fact that you are unable to make sushi for a while until the wound is properly sealed and also the fact that you must wear protective gears like gloves and Band-Aid, both of which make your sushi making very awkward and uncomfortable.
Toshi told me to sharpen my knife only during my break or off hours, never during my shift. I had difficulty understanding this in the beginning and later, I realized why: a chef should always have his knives sharpened and ready to work, just like a soldier takes care of his weapons, always ready to go on a battle at any moment’s notice.
As simple as the knife sharpening technique is, it took me several years just get comfortable gliding my knife on a Whetstone. I can understand why many chefs send their knives to a sharpening professional to have the knives sharpened since it really is a difficult thing to master. I am, unable to say that I have mastered knife sharpening, but I can say I’ve done enough to sharpen and take care of my knives good.