Sashimi | Sushiblog－Sushiuniversity

What is Sashimi?

a photo of sashimi — A plate of assorted sashimi

Sashimi (刺身) is a Japanese dish made by removing the inedible head, bones, skin, fins, and tail from seafood such as fish, squid, octopus, or shellfish, and in some regions from meats like whale, horse, or chicken, and then slicing it into small, easy-to-eat pieces.

Sashimi is sometimes mistaken for sushi without the rice, but the two are considered distinct dishes in Japanese cuisine. Sushi refers to vinegared rice combined with seafood or other toppings, while sashimi focuses solely on the sliced seafood (or other ingredients) itself, served without rice.

It is considered the ultimate washoku dish, but why is such a simple and uncooked dish regarded so highly? Although sashimi is often described as “raw,” it does not always mean completely uncooked. Some varieties are lightly seared on the surface (aburi) or briefly blanched in hot water (yubiki) to enhance flavor, aroma, or texture while keeping the interior mostly raw.

In Japan, ingredients that are fresh enough to eat raw are considered more valuable, and sashimi preparation in particular requires substantial labor and technique. Seafood served as sashimi must meet strict hygiene and safety standards. Depending on the species, it may be flash-frozen at −20°C (−4°F) or lower for a set period to eliminate parasites, as required by food safety guidelines. From the moment it is caught, the fish is handled to minimize bacterial growth, often using the ikejime method to stop nerve activity and preserve texture. It is then transported under strict temperature control, prepared with sterilized knives and cutting boards, and served immediately to maintain peak freshness and flavor. These measures ensure that sashimi is both safe to eat and of the highest possible quality.

Its preparation begins when the fish is first taken out of the sea. The fishermen perform Ikejime, a technique that shuts off the fish’s neurotransmission in order to preserve freshness and texture while the fish matures.

Each fish has its peak, which is referred to as shun (season), and chefs train for years to develop their ability to determine whether a fish is fresh and its peak. The carefully selected fish is cut into smaller pieces in one stroke with a sashimi boucho (knife), which creates a smooth surface. If the meat is cut with an unsharp knife, it will be crushed and the result will be watery and tasteless.

The chefs pursue pleasing texture, ease of eating, and delicious flavors by varying the thickness of cuts and cutting techniques, depending on the type of seafood they work with.

It is popularly served with soy sauce and condiments such as wasabi, and such garnishes as shiso and shredded daikon radish.

As an aside, sushi restaurants offer a variety of sashimi cuisine. You can order them as assortments, not to mention as single dishes of tuna, sea bream, squid, horse mackerel, or shellfish among others. If the shop has seasonal fish in stock, it might be a good idea to leave your order to the chef.

[sc_apply url=”https://sushiuniversity.jp/apply/”]

We hope this information will be helpful.

Revision date: August 12, 2025

Share this article

What is Kaiseki Ryori?

Kaiseki Ryori (会席料理) is a course meal to enjoy banquest style. In a typical menu, appetizers (前菜), soup (吸い物), sashimi, grilled dishes (焼き物), simmered dishes (煮物), deep-fried dishes (揚げ物), steamed dishes (蒸し物), and vinegared dishes (酢の物) are delivered in order, and finally rice and red miso soup (止め椀), pickles (香の物), and fruits (水菓子) are served. Some restaurants add an aperitif (食前酒).

The most familiar example of Kaiseki Ryori is the food served at hot spring resorts.

[sc_apply url=”https://sushiuniversity.jp/apply/”]

We hope this information will be helpful.

Revision date: December 29, 2022

Share this article

What is Sekisaba?

Sekisaba (関サバ) and Sekiaji (関アジ) are ‘designer’ fish known for their high prices.

Of them, Sekisaba is a premium fish that can go for as high as US $50 per fish. So, what kind of fish is Sekisaba and what’s the difference between it and normal Saba (Mackerel)?

Sekisaba is a Saba caught in the Hoyo Strait with a fishing pole by a union member of the Saganoseki branch of the Oita National Federation of Fisheries Cooperative (JF Oita). In other words, Sekisaba is not a type of Saba, but a premium fish created by differentiating the fishing method.

Sekisaba started to become known all over Japan between the late 1980s and early 1990s. Until then, Sekisaba was only known as a commonplace fish that was caught incidentally with Aji and went for US $2 per fish.

However, the Saganoseki branch of JF Oita applied for the first trademark ever in the industry and then grew the brand through methods such as tagging each individual fish by hand. This resulted in recognition of its taste as “Saba that can be enjoyed even as sashimi” (while Saba is generally a fish that loses its freshness easily and not eaten raw), catapulting it to a national constituency After that, the thorough quality management and branding paid off and the price jumped to 10 times that of normal Saba.

The first difference between Sekisaba and normal Saba is that Sekisaba is caught carefully, one at a time. The use of ground bait is also banned so that the Sekisaba won’t eat anything but the natural diet (avoiding odor). Each fisher is only allowed to use fishing lures they make from fish skin or ragworms. Fish caught in this way are let out into a live holding tank on the ship and brought to the fishing port alive. After arriving at the port, the tank on the ship is checked, the fish size is looked at from the water surface and the approximate weight is measured. This method is called “Tsurugai”. This is because when the fish is placed on a scale, it struggles violently and can injure itself. The fish are allowed to calm down in the tank (called Ikekoshi) for a day at the fishing port. At the time of shipping, Ikejime is performed, in which a knife is put into gill parts, the spinal cord is cut, and then it is submerged into saltwater and the blood is let out. After that a processing method called Shinkeijime is performed in which a wire is inserted into the spinal cord to put the fish in a state of asphyxiation. Therefore, there is little damage to the fish, maintaining the freshness. When it is transported to the place of consumption, the temperature is kept at 5°C (41°F). This is because the fish does not lose its crunchiness compared to when it is cooled to 0°C. Even this is not easy to imitate.

The Hoyo Strait where Sekisaba is caught is rich in plankton, which the Sekisaba feeds on, and the flow of the tide is fast. The reason Sekisaba meat firms well and is fatty year-round is thanks to the good environment of the sea it is raised in.

If you come across a Sekisaba that so much work has been put into, try it as sashimi, not Nigiri sushi. This is because Saba, which has a peculiarity to it, is unpopular among some people. However, Sekisaba doesn’t have this off-taste and doesn’t taste like Mackerel, so even people who don’t care for fish should be able to find it tasty.

[sc_apply url=”https://sushiuniversity.jp/apply/”]

We hope this information will be helpful.

Revision date: August 21, 2023

Share this article

What is ken?

Ken (剣) is a traditional Japanese garnish made from finely shredded vegetables like daikon radish. It is often seen alongside sashimi. While commonly mistaken for tsuma, ken has its own distinct role in Japanese plating and presentation.

It is not merely decorative—it helps absorb moisture, maintains freshness, and enhances the visual balance of the dish.

Ken is considered to be better the longer and thinner it is, but this is a mistake. Not only is Ken tangled and difficult to eat, but it also doesn’t give any sense of the flavor of the materials. It’s long been said that 10 cm is a reasonable length and this is also the length that looks the most refined. Creating ken requires precise knife skills, and its neatness often reflects the chef’s craftsmanship.

Many people believe that the thinly cut daikon radish strips that accompany sushi are tsuma. That is not tsuma. It’s called ken. Besides daikon radish, udo, pumpkin, cucumber, carrots and turnips are also used. It is cut into thin strands and stood up next to sashimi like a sword (which is called “ken” in Japanese). However, when the sashimi is laid on top of it, it is called shikitsuma. While it is a bit confusing, in that case it is a type of tsuma. The simplicity and elegance of ken align with the Japanese aesthetic of minimalism and natural beauty.

Since the Meiji era, combos of many different types of sushi have become popular, and with it larger dishes have become necessary. Therefore, there has also been a tendency to make it more showy. It’s only natural that the types of tsuma increase to place focus on the highly valued seafood, but if there is too much ken, it will take over the space meant for the sashimi.

What is Tsuma?

In Japanese cuisine, “Tsuma” refers to ingredients that are added to sashimi, soup dishes, and other dishes to enhance their color and flavor. Many people think that the shredded daikon radish served with sashimi is “Tsuma.” However, this is actually called “Ashirai,” and depending on how it is cut and where it is placed, it is classified into three types: “Tsuma,” “Ken,” and “Yakumi.”

More specifically, Tsuma itself can also be categorized into three types.

One is Shikitsuma (pronounced ‘shikizuma’ in Japanese) which consists of things like green shiso and cucumber leaves that sashimi is laid on. Another is Metsuma (pronounced ‘mezuma’ in Japanese) which is made from aome and murame. The final is Tatetsuma (pronounced ‘tatezuma’ in Japanese) used to prop sashimi up like hanahojiso and hanamaru kyuri (花丸胡瓜又は花付き胡瓜). All Tsuma is served to bring out the charm of sashimi.

One point of note is that the most commonly used shikitsuma, green shiso, is occasionally used to obstruct fragrances that are too strong for white fish and shellfish like flatfish and flounder. Furthermore, it’s a rule that shikitsuma, which is a leaf, is not used on plates shaped like a leaf, but what is served and how it is arranged is ultimately up to the chef.

In the end, Tsuma is not merely a garnish—it is an integral part of Japanese culinary aesthetics, harmonizing taste, seasonality, and visual beauty.

Image of Metsuma: Aome (Here, ao refers to green) is on the left and murame (Mura means purple) is on the right in the image.

Image of Hanahojiso (花穂紫蘇): It is the spike of perilla with flowers about to bloom.