Katsuobushi (A Dried Bonito) (鰹節)

Katsuobushi (dried bonito) is a Japanese preserved food made from bonito.

The bonito is filleted into three parts or more, and basically it's only after these fillets are cut in 'fushi' (the shape of a wooden ship) and processed that the fillets can be called katsuobushi.

Katsuobushi is divided into three categories according to the phases of processing: namaribushi (a fillet just simmered), arabushi (a smoke-dried fillet after being simmered) and karebushi (a fillet matured by mold-coating to absorb the moisture). The commonly known katsuobushi is the last one, but in a broad sense all the above-mentioned three are called katsuobushi. The name 'katsuobushi' was used even before the Edo period, when the smoke seasoning method was invented.

Katsuobushi contains a large amount of inosinic acid (the source of its good taste), so it's often used as a seasoning in Japan. It's also rich in B vitamins and other nutrients.

The kind of katsuobushi sprayed with fungus, which is called "karebushi," includes more flavor ingredients and vitamins than other kinds, so it's traded as a luxury.

Processed foods similar to Japanese dried bonito are found in the Maldives and other places.

Before the age of the smoke seasoning method

Bonito has been eaten by the Japanese since ancient times, and there is evidence showing that people ate it as long ago as the Jomon period (as exemplified by the Hachinohe ruins in Aomori Prefecture). Apparently, dried bonito was made in or around the fifth century, but it seems to have been quite different from the present varieties; a record states that there were methods of producing dried bonito, but they seem to have produced something like stockfish.

In 701, during the Asuka period (the period from late in the sixth century to 710), dried bonito and other products were designated in Taiho Ritsuryo (Taiho Code) and Buyaku Ryo (Corvee Code) as the offering to the Yamato Court; the products related to bonito were classified into three categories differing in their production processes, namely 'katauo' (a solid dried fish), 'nikatauo' (a fish boiled and dried hard) and 'katauo senju' (a soup stock extracted by boiling a solid dried fish). Of the three, 'katauo' was designated as the offering from the provinces of Izu, Suruga, Shima, Sagami, Awa (the present-day southern Chiba Prefecture), Kii, Awa (the present-day Tokushima Prefecture), Tosa, Bungo and Hyuga.

It was in the Muromachi period (1338 to 1573) that dried bonito relatively similar to the present one was produced.
Shijoryu Hochogaki' (A Cookbook of Shijo School) (a school of Japanese cuisine), which is said to have been written in 1489, mentioned 'hanakatsuo.'
This could have been a considerably hard material rather than just a stockfish, because it seems to have comprised shaved pieces of a bonito product.

Establishment of the smoke seasoning method

In the Edo period, a man called Jintaro in Inamiura, Kii Province (the present Inami-cho, Hidaka-gun, Wakayama Prefecture), devised the smoke seasoning method (also called the roast seasoning method), which removed the moisture from the fish by smoking, thereby making the product similar to today's arabushi. The katsuobushi thus produced with the roast seasoning method was called Kumano-bushi (katsuobushi produced in Kumano), and this was so popular that the entire Tosa clan introduced the method into their own katsuobushi production.

Far from consumers in cities such as Osaka and Edo, katsuobushi producers in Tosa Province were troubled by the katsuobushi's tendency to mold, but they turned the problem to their advantage by devising a way of seasoning katsuobushi with the very fungus that attacked it. Thus the improved Tosa-bushi (katsuobushi produced in Tosa) was able to withstand not only the long-term transportation to Osaka or Edo but also the long-term preservation in consumer cities; it tasted good as well, so it gained wild popularity and reached its prime. The method of producing the improved Tosa-bushi was kept secret, except for people in the hometown of Jintaro, who taught people in Tosa Province the smoke seasoning method. However, a man called TOSA no Yoichi taught people in Awa Province the Tosa method in 1781, and he then taught it to those in Izu Province in 1801; additionally another person taught it to those in Satsuma Province. Subsequently, Tosa-bushi, Satsuma-bushi and Izu-bushi began to be called the three best-known types of katsuobushi in Japan. At first, the fungus, with which katsuobushi was seasoned into karebushi, was generated spontaneously. However, in the Showa period a pure culture of Aspergillus glaucus (a kind of aspergillus) began to be sprayed on katsuobushi, not only to shorten the period of processing but also to prevent unfavorable fungus from generating, and thereafter this method became mainstream.

Later, large amounts of katsuobushi were produced in Pacific coastal provinces such as Satsuma, Tosa, Awa, Kii and Izu, which had large catches of bonito.. In the Edo period, the domestic marine transport became active, so the katsuobushi produced in Kyushu or the Shikoku region was transported to Edo and people there jokingly made a katsuobushi ranking list, in which 'Shimizu-bushi' (the katsuobushi produced in Shimizu, Totoumi Province (the present-day Shizuoka Prefecture)) and 'Yakushima-bushi' (the katsuobushi produced on Yakushima Island, Satsuma Province) was ranked ozeki (the second-highest rank of a sumo wrestler).

cf. Nationwide katsuobushi ranking list in 1822

Ozeki

Shimizu-bushi (the east side, Totoumi Province)/Yakushima-bushi (the west side, Satsuma Province)

Sekiwake (the third-highest sumo rank)

Usa-bushi (the east side, Totoumi Province)/Gozen-bushi (the west side, Tosa Province)

Komusubi (the fourth-highest sumo rank)

Fukushima-bushi (the east side, Totoumi Province)/Suzaki-bushi (the west side, Tosa Province)

Subsequently, the list was followed by the introduction of gyoji (a sumo referee), maegashira (the fifth-highest sumo rank), sewagata (sponsor) and kanjinmoto (promoter).

Incidentally, Tosa-bushi and Satsuma-bushi were generally applied to the katsuobushi produced in the provinces of Tosa and Satsuma, respectively.

Katsuobushi fairs were held nationwide, such as 'the First Fisheries Exhibition' in Ueno Park, Tokyo, in 1883, and 'Japan Fisheries Association's First Katsuobushi Fair and Spot Sale' in 1908, and at those fairs Yaizu-bushi (of eastern Japan) and Tosa-bushi (of western Japan) were highly evaluated for their quality. During the Meiji period, katsuobushi also started being produced in Uotsurijima Island, of the Senkaku Islands, and in the South Sea Islands (which were then Japanese territories as mandated by the League of Nations). Particularly, the katsuobushi produced in the South Sea Islands was so low-priced as to expand its market greatly, but the katsuobushi industry in this area was brought to a close when the South Sea Islands were removed from Japanese control after World War Ⅱ.

Quality improvements of kezuribushi (thinly shaved pieces of katsuobushi)

The well-drained katsuobushi could be prevented from decaying during long-term preservation, but it continued to be troubled by pests, including buffalo bugs, as well as by harmful mold. In the Taisho period, the Fujiwa Abe Store in Fukuyama City, Hiroshima Prefecture, devised a way to wrap the kezuribushi in a paper bag for shipping. This kezuribushi offered the benefit of saving consumers from having to shave katsuobushi, but it still had the disadvantage of losing its savory aspect due to deterioration.

The research and development continued for a kezuribushi that could retain its savory aspect, and in 1969 the Ninben Co., Ltd., released the product called 'Fresh Pack.'
This product succeeded in retaining that savory quality for a long period by adopting three-layered synthetic resin as a wrapping and by filling the wrapping with inert gas to displace the oxygen. Consequently, it became a red-hot product; other companies released similar products, which drove the katsuobushi kezuriki (a cutter box for katsuobushi) from the Japanese household. Today, various amounts (or kinds) of kezuribushi are put on the market to meet various consumer demands.

The uses

Katsuobushi is regarded as a basic Japanese seasoning, and it's an indispensable ingredient for soup stock along with konbu (a kind of kelp). It's also used as a light, finishing garnish atop various dishes.

The two fillets cut away from the two sides of the bonito's spine are called "kamebushi"; the four fillets yielded by halving the two blocks of kamebushi are called "honbushi"; the back part of honbushi is called "osubushi" (or "sebushi"), and the belly part of honbushi is called "mesubushi."

In the past, each Japanese household used to have a 'katsuobushi kezuriki' (a cutter box for katsuobushi), since it was necessary to shave the katsuobushi with it just before cooking it. This implement, converted from a carpenter's plane, had a small box in which the blade was positioned upward, and the small box had a drawer from which the shaved katsuobushi pieces were removed. This device's formal name is 'ogurashiki katsuobushi kezuriki (Ogura-style cutter box for katsuobushi). One cannot be too careful when using the katsuobushi kezuriki, because one could get injured by the blade when trying to shave a lump of katsuobushi.

Nowadays, it is rare for katsuobushi to be sold in the form of fushi (the fillet cut in the shape of a wooden ship), and the popular one is kezuribushi (thinly shaved pieces of katsuobushi) in a small bag that is made airtight with nitrogen; nevertheless, those who prepare high-quality Japanese cuisine are said to shave fushi just before cooking, attaching importance to the savory aspect.

Generally, 'hanakatsuo,' meaning the pieces shaved from 'arabushi,' are often used for the soup stock, but it's said that most high-class Japanese restaurants use the pieces shaved from 'karebushi.'

Incidentally, 'arabushi' is, in the list of product contents, expressed as 'katsuo-fushi' with the country origin shown next, and it's used as the material of 'katsuo kezuribushi' (high-quality shaved pieces of katsuobushi). Meanwhile, 'karebushi' is, in the list of product contents, expressed as 'katsuo-karebushi,' and it's used as the material of 'katsuobushi kezuribushi' (extra-high-quality shaved pieces of katsuobushi).

There are also various shaving methods, among which the commonly known ones are 'specially thin shaving' (the method mainly used to make a topping), 'thick shaving' (the method mainly used to make the material for soup stock) and 'thin shaving' (the method used for both).

The katsuobushi that is boiled down in (or tossed with) soy sauce is called "okaka," and this is popular as a stuffing for rice balls.

Moreover, to provide a rich flavor, powdered katsuobushi is sprinkled on top of takoyaki (a ball-shaped pancake containing small pieces of octopus) or okonomiyaki (a Japanese-style pizza containing one's favorite vegetables and other ingredients). The katsuobushi that is shipped to market is rarely made into powder, but in many cases the crumbs or fragments produced during the production process are recycled into powder and placed on the market.

An example of a traditional method of katsuobushi production

A bonito is cut into its various parts. The bonito is filleted by removing the head and entrails, and then the fillet is cut into fushi (the shape of a wooden ship).

A basket is lined with the fillets and is simmered in an iron pot for about 100 minutes. The temperature must be carefully controlled.

The fillets, upon being removed from the pot, are scaled, and the fat and bones are removed from them. At this point, the fillet is still soft but can be used as a foodstuff called "namaribushi" (or "namabushi") without any further processing.

The fillet is smoke-dried. Oak or chinquapin is used for smoke-drying. This process will, if necessary, be repeated several times.
The fillet finishing this process is called 'arabushi,' which is the material of so-called 'hanakatsuo.'

The fillet shaved of its surface dirt (called "hadakabushi") is drained, and then it's dried in the sun. Subsequently, the fillet is sprayed with a pure culture of Aspergillus glaucus, and it's kept in a tightly closed room so that the fungus will multiply.

Once the fungus has multiplied, the surface of the fillet is shaved off and step number 5 is repeated.

By repeating step numbers 5 and 6, the fillet becomes tough like wood because it no longer has any moisture, and it will no longer be subject to mold.
The fillet's weight becomes less than 20% of what it was before processing, and this process completes the production of 'karebushi.'
Hit a good-quality karebushi against another one, and there will be a clanging sound similar to what one hears when striking a piece of hard timber against another piece. Break a karebushi in two, and there will be a cross section having a clear, deep-red color resembling a ruby.

Similar products

In addition to bonito, the following fish products processed in a similar way, though most of them are at best arabushi:
Sodabushi (dried bullet mackerel)
Sababushi (dried blue mackerel)
Magurobushi (dried tuna)
Ajibushi (dried scad)
Iwashibushi (dried anchovy or sardine)

Recently, similar processing has been attempted with saury and herring, given the surplus fish available from large catches.

In Hokkaido and some prefectures of the Tohoku region, attempts have been made to process the fish of dead chum salmon following the run up a river and spawning roe, into 'sakebushi (dried chum salmon),' because the raw fish tastes bad and is therefore inedible.

Others
Today, the common knowledge about katsuobushi from many years ago is forgotten, and most of the public aren't aware that fungus-covered fushi is a luxury. When one is really particular about the savory quality of katsuobushi, he or she will purchase a large chunk of katsuobushi instead of shaved pieces, but nowadays the katsuobushi shaved beforehand and wrapped in a small, airtight bag is so popular that many people have never seen the solid katsuobushi.

Frequently, those who are given a gift of karebushi (fungus-sprayed katsuobushi) will discard it because they don't know the value of fungus-covered katsuobushi and mistakenly think it has gone bad. Accordingly, katsuobushi manufacturers have come to attach instructions to their products, but still there is no end to the discarding of fungus-sprayed katsuobushi, they say; in the first place, the utensil used to shave katsuobushi has disappeared from the modern Japanese household.

Incidentally, in the Indian Ocean island nation of the Maldives, a dried food called 'Maldivian fish' similar to Japanese katsuobushi is produced. The Maldivian fish is used as a seasoning in the surrounding areas, including Sri Lanka.

In 1975, John Lennon released his album "Shaved Fish," which compiled his popular singles issued after the breakup of the Beatles, and in this case the term "shaved fish" is said to mean katsuobushi. He is thought to have implied that his music had various purposes, like katsuobushi.

Katsuobushi is also regarded as 'the toughest food in the world,' so it was once used as a general term for any tough material.