Does a Sushi Chef Really Need That Much Skill To Make Sashimi?
By: Kaz Matsune
Tags: Sushi, Sushi Chef, Food, Japanese Food

Photo by Jongsun Lee on Unsplash

Q: Pure sashimi is just nicely cut fresh fish. The fresher the fish, the better the taste. So what exactly is the top sushi chef in the world really doing?

After being a professional sushi chef for over nineteen years, I can say that sashimi is one of the most difficult techniques a sushi chef can master.

Why is it so difficult? Isn’t it just slicing a fish?

First, the definition of sashimi.

What is Sashimi?（刺身）

Sliced meat. When Japanese say sashimi, they usually assume it to be “raw fish” sashimi. Other varieties of Sashimi are Chicken Sashimi, Yuba (bean curd) sashimi, and Konnyaku (a type of potato) Sashimi.

What Sashimi is NOT

Raw fish is not sashimi. Sashimi is not always raw fish.

How to make sashimi?

There is a bit of science and physics involved in making great tasting sashimi. Sashimi needs no cooking, prepping, marinating or saucing. What a chef wants to achieve is to preserve the maximum flavor of the ingredient. To do so, a chef should minimize the damage to the ingredient when slicing with the knife.

Tuna and Yanagiba Knife, Photo by cottonbro from Pexels

Sashimi knife, called Yanagiba, a willow-leaf knife is designed to slice fish. (writer’s note: many people think there is a sushi knife, but there is no such thing as a sushi knife. Sushi chefs use Yanagiba, sashimi knife.)

When making fish sashimi, a sushi chef will hold the knife and move it backward, making a single stroke. In Japanese, this is called “to pull Sashimi.” I never heard of anyone saying this in English. Still, if I were working with Japanese sushi chefs, I would be asked to “pull sashimi” instead of “make sashimi” in Japanese. The backward motion is not straight backward, but somewhat slightly curved movement, which reduces friction.

The narrow shape of the Yanagiba knife is designed to reduce the friction when slicing.

Why less friction?

Less friction means less damage to the ingredient, specifically less damage to the millions of cells of the ingredient holding the flavor (taste and aroma). Less damage, more flavor. Chef’s technique (how to “pull” the knife) and the shape of the knife (long and narrow) both contribute to the flavor of sashimi.

Now the three reasons why sashimi is difficult.

1. Slicing straight in equal width

Have you ever sliced a long loaf of bread into equal width? If you haven’t, I encourage you to try at least once. If you have done that, you know what I am talking about here. It is extremely difficult to make a straight sliced piece from a loaf of bread. Your knife wobbles and the one end comes out angle.

Slicing fish sashimi with all the pieces with a straight edge is also difficult. When I started practicing sashimi, none of the pieces came out straight. I could not understand why. One of the reasons I read in a book was how I was seeing the knife. Because of the way Yanagi is designed, I need to adjust how I stand and how I look at my knife and a block of fish.

To slice even pieces was another challenge because I had to “eyeball” each slice. It’s like learning how to play the guitar with no fret (it’s the raised bar indicator on the neck). The only way to master this is to practice — pull as many slices of sashimi as you can.

2. To slice fish beautifully is very difficult

Yes, anyone can slice a fish. To do it very gracefully and beautifully, it takes practice — a lot of practice.

The metaphor I use is learning a musical instrument such as drums or piano. Drumming is hitting with sticks and piano is hitting the keys with your fingers. How hard could they be? Very.

Sashimi is the same.

First, fish is softer. Its flesh is soft and tender.

In my sushi class, I teach attendees to use less force. This can be very confusing. It is challenging because when we experience difficulty cutting ingredients, our tendency is to use more power. When slicing fish, it’s the complete opposite — the less force, more slicing. The idea is to use the sharpness of the knife and let it “slide” by itself. In Japanese, it is called “let your knife run.” All you are doing is to guide your knife as if you are assisting it to do the slicing, not you. This was only the first step, and it took me several years to feel comfortable slicing a fish for sashimi.

3. You have to know the fish just by looking at it

Each fish tastes different. Male salmon tastes different from female salmon. Can you tell the difference just by looking at it? Yellowfin Tuna is different from Bigeye. How thick should you cut tuna belly? Should you cut back of tuna the same thickness as the belly? How about halibut? How should you cut it? Should you cut the fish against the grain or along the grain? There are lot of details going into just “slicing” fish sashimi.

In general, tuna tastes good when cut thick around 1cm-2cm or 1/2–1inch for sashimi. When cut into paper-thin, tuna loses its flavor.

However, when it comes to Toro/Tuna Belly, you need to cut it thin due to its fat content. If you cut Toro into 2cm thickness, it may be too overwhelming, thus killing the delicate flavor the belly meat has.

You see that how you cut determines how the sashimi tastes. You need to be able to determine just by looking at the fish. This takes years of experience — looking at fish every day for many years. Let’s just say even if you mastered sashimi knife skills but you know nothing about fish. You are unable to make the great-tasting sashimi because you have no idea how to slice it for great taste.

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