What is Iwashi イワシ [鰯]?
In Japan the term iwashi refers to a group of sardines and anchovies. Additionally, many (unrelated) fish include the term iwashi in their name.
In Japanese cuisine, iwashi refers primarily to the Japanese sardine. The term is also occasionally used for the Japanese anchovy or the red-eye round herring. From these three types, the Japanese sardine, whose correct designation is ma iwashi, literally the "real sardine", represents the most important species. The Pacific sardine, in addition to the Japanese sardine, is nowadays being used in Japanese cuisine and can therefore also be considered as iwashi in a broader sense.
All species are of high commercial importance, are extensively fished and industrially processed.
Iwashi for Sushi and Sashimi
Iwashi is considered a delicate fish that must be processed carefully and quickly. Since iwashi decomposes rapidly, it develops an unpleasant odor early after being caught and is therefore only available in limited quantities for sushi or sashimi. To maintain freshness iwashi is either soaked in 3 to 5 percent salt water or previously sprinkled with salt and then placed in a mixture of ice water and vinegar. The osmotic effect of the salt solution has a slightly preservative effect, reduces the odor and maintains the shiny skin surface characteristic of iwashi.
With plump in-season iwashi, the fatty layer in between the skin and the flesh is amazingly thick. Despite that, it neither smells fishy nor tastes greasy. Jiro Ono in Sushi Chef: Sukiyabashi Jiro (Satomi, 2016)
Ginger and spring onion are suitable as side dishes, ginger also has a neutralizing effect on the smell. Especially fresh specimens harmonize very well with wasabi alone. In upscale sushi restaurants, ginger and spring onions are sometimes pressed into a paste, refined individually and placed on top of the nigiri coated with soy sauce. If iwashi is prepared as sashimi, soy sauce mixed with ginger is very suitable.
The spawning times of ma iwashi depend on the region and population, therefore no exact season can be determined for sardines from the group of ma iwashi. In Japan the months from June to October are traditionally considered to be the tastiest time of year for Japanese sardines. The spawning season of the european sardine (yōroppa ma-iwashi) also varies considerably by region and population, with the main fishing season beginning in late spring and ending in late summer.
Urume iwashi is caught all year round, but it is said that the best season is from winter to early spring, when the fish have become fattier.
Katakuchi iwashi migrates from the East China Sea to the coastal region of Taiwan to spawn in late winter and early spring. Therefore summer is considered the best season for katakuchi iwashi.
Iwashi caught between spring and summer are also considered particularly tasty and are called baiu iwashi (rainy season) or nyuubai iwashi (beginning of the rainy season).
Iwashi in Japan
In Japan, October 4 has been the official sardine day since 1985 (イワシの日). The day was created by the Iwashi Promotion Association (いわし普及協会) with the aim of encouraging the acceptance of sardines as a cheap and tasty fish. In Japanese, October 4th is written as 10月4日, resulting in a pun that reads iwashi (1 → い [i], 0 → わ [wa], 4 → し [shi]) (Kase, 2009).
Ma iwashi マイワシ【真鰯】
The most common iwashi species found on Japanese dining tables is Japanese sardine (ma iwashi), which also serves as a eponym for its associated species. Of all iwashi species, it is most commonly used for the preparation of sushi or sashimi.
The Japanese sardine is a submember of the species Sardinops sagax. Accordingly, all representatives of this species are understood as ma iwashi, literally "real sardine". The population of ma iwashi is divided into five different subspecies, chiri ma iwashi in the waters around Chile, cariforuniama iwashi in California, ma iwashi in Japan, ōsutoraria ma iwashi in Australia and minami afurika ma iwashi around Africa. The European sardine, because of its similarity, especially in taste, is also culinary counted to ma iwashi and is called yōroppa ma iwashi.
|Japanese name||Common name|
Sardinops sagax melanosticus
|Ōsutoraria ma iwashi
Sardinops sagax neopilchardus
|Minamia furika ma iwashi
|Southern African pilchard
Sardinops sagax ocellatus
|Kariforunia ma iwashi
Sardinops sagax caeruleus
|Chiri ma iwashi
|South American pilchard or Chilean sardine
Sardinops sagax sagax
|Yōroppa ma iwashi, Nishi iwashi
The Pacific sardine usually occurs within large schools in coast-proximity. Young animals feed on zooplankton, adult animals mainly on phytoplankton.
In the years from 2000 to 2018, the Japanese sardine accounted for an average of 21 percent of the global catch of the ma iwashi group. The share of the european sardine was 54 percent. Ma iwashi is mainly used for the production of processed products up to the production of fishmeal, only a small percentage is used as fresh fish.
Urume iwashi ウルメイワシ【潤目鰯】
The taste of the red-eye round herring (urume iwashi) is the most distinctive of all sardines belonging to the group of iwashi. Urumeiwashi is therefore very suitable for the preparation of Sushi or Sashimi.
Urume iwashi is caught in much smaller quantities than ma iwashi and katakuchiiwashi. Therefore, urumeiwashi appears less frequently at markets and is therefore rarely found in sushi restaurants. Furthermore, urumeiwashi, like all sardines, is very sensitive and must be processed quickly after the catch. Urumeiwashi is often dried and prepared on a skewer and offered as urumeiwashi no mezashi (ウルメイワシのメザシ).
Urumeiwashi lives in tropical and temperate waters not only in Japan but all over the world. They swim in shoals near the sea surface and feed mainly on plankton.
Katakuchi iwashi カタクチイワシ
The Japanese anchovy (katakuchi iwashi) is the smallest representative of iwashi fishes with an average length of 10 cm. Only the freshest specimens are suitable as sashimi and are highly appreciated for their good taste. A large part of the landed katakuchi iwashi are industrially processed as canned or dried fish. Juveniles or the immature fish fry are prepared into shirasu (しらす) and chirimenjako (ちりめんじゃこ).