Kohada Sushi

In Japanese, kohada stands for a medium-sized dotted gizzard shad (konoshiro) which belongs to the herring family. Kohada is considered a classic ingredient of blue-backed fish (aozakana, 青魚) for edomae sushi and is especially popular in East Asia.

Kohada is not only a popular ingredient for the preparation of sushi or sashimi, it is also a symbol for the philosophy of Edomae sushi among connoisseurs and chefs alike. Because of its fresh, shiny appearance (hikarimono, 光り物), it is considered one of the most beautiful sushi dishes, which reaches its peak in flavor only when properly prepared and combined with sushi rice.

“

Kohada is the cheapest fish among all sushi neta (sushi ingredients, typically fish), but if you prep it well, it turns into the “Yokozuna of Nigiri”.

- Jiro Ono, Sushi Chef (Sukiyabashi Jiro) [Satomi, 2016]

When the meat of kohada is salted and marinated in vinegar (sujime-method), an exceptionally full-bodied taste is created, which harmonizes wonderfully with the subtle sweetness of sushi rice. In addition, the marinating process reduces the strong taste and softens any bones that may still be present. The duration of application and dosage of salt and vinegar are adjusted according to the size of the fish, the amount of fat and the season, so that a lot of experience in preparation is required. It is said that hardly any other fish can vary so much in taste by treatment with salt and vinegar. Therefore, it is said that kohada is a measure of the skill of the chef or the quality of a sushi restaurant, as the taste changes significantly depending on the amount of vinegar and salt used. Depending on the size of the fish, either the whole fish can be used or up to four whole specimens of smaller size (see shinko).

The taste of kohada sushi is characterized by mineral aromas accompanied by a buttery sweetness and subtle acidity. The range of possible side dishes or garnishes is wide and ranges from crystallized egg yolk (kimi oboro) or shrimp paste (oboro) over citrus fruit (yuzu) to an individually refined soy sauce (nikiri shōyu, 煮切り醤油).The sauce is often applied as a thin glaze to the fish before it is served as nigiri sushi. Besides its wonderful rich and fatty taste, the meat is rich in proteins, essential fatty acids and trace elements.

Best Season

The spawning season begins in early spring and ends in early summer, with some fish spawning twice or more [Takita, 1978]. The season for small fish named shinko starts in July and ends in August. Medium sized specimens with the name kohada are mostly caught between August and September. Large specimens of the konoshiro are caught all year round, but are most palatable in the winter period from November to February.

A fish that changes its name

Kohada belongs in Japan to the “rising or ascending fishes” (shusseuo), this refers to fishes that change their name depending on size and age. A dotted gizzard shad carries the name Sshinko up to about 5 cm total length, from a size of 7 to 10 cm it is called kohada. As soon as it reaches 13 cm, it carries the name nakazumi, in order to then be called konoshiro as adult fish from a length of 15 cm. For the preparation of a nigiri sushi, depending on the size of the fish, either whole or multiple specimens of the size shinko are used. Large specimens (konoshiro) are rarely used for the preparation of sushi or sashimi, but are suitable for other types of preparation.

If you look at the growth in value of the konoshiro, you can almost mockingly claim that it is a “descending fish”, because with increasing size its value and thus its selling price decreases. Especially for the preparation of sushi, smaller sizes like kohada or shinko are appreciated.

The distribution area extends along the coast of the Japanese archipelago over the Korean peninsula to the East China Sea. The dotted gizzard shad is only slightly migratory and does not change its habitat significantly during its life cycle. Its diet consists mainly of plankton, diatoms and small crustaceans.

Konoshiro is only of minor economic importance. According to the Food and Agriculture Organization of the United Nations (FAO), Japan is the only country that fishes Konoshiro in industrially relevant quantities. Since 2005, South Korea has been producing Konoshiro from aquaculture. [FAO FishstatJ, 2020]

Gallery

Distribution Area of Kohada

1. SCOMBROTOXIN: The naturally have high levels of enzymes causes the meat to let it rot quickly. It is therefore essential to maintain an appropriate cold chain until prompt processing. Histamine is not destroyed by normal cooking temperatures, so even properly cooked fish can still result in poisoning. [FDA, 2021]
2. PARASITES: The meat, especially that of wild-caught specimens, may be infested with parasites that cause infectious diseases. Infection can be avoided if the raw meat has been adequately frozen. Pickling and soaking in salt or vinegar solution is not sufficient to eliminate the parasites. If the product has been farmed, only raw unprocessed seafood from production facilities whose products are approved for raw consumption should be consumed. [Choi et al., 2011]

Image Credits

1. T.Tseng. Kohada, Mori Sushi, West LA. flickr.com. License: Attribution 2.0 Generic (CC BY 2.0). Changes made: image quality, brightness, contrast, colour matching, sharpening, cropping.

2. City Foodsters (Grace Chen, Jason Wang). Kohada, Sushi Yoshitake, Tokyo, JPN. flickr.com. License: Attribution 2.0 Generic (CC BY 2.0). Changes made: image quality, brightness, contrast, colour matching, sharpening, cropping.

3. Dennis Schilder. Kohada Nigiri Sushi (Tokyo) こはだ 握り寿司 [すしざんまい 築地駅前店]. License: copyrighted ©.

4. T.Tseng. Kohada, Sushi Ya すし家, Ginza Chuo Tokyo. flickr.com. License: Attribution 2.0 Generic (CC BY 2.0). Changes made: image quality, brightness, contrast, colour matching, sharpening, cropping.

5. City Foodsters. IMG_2950. flickr.com. License: Attribution 2.0 Generic (CC BY 2.0).