Kikkoman Corporation

Food ingredients preserved by the drying process of kanbutsu are part of a millennia-old indigenous food culture. This is the first of a four part series introducing Japan’s dried food products.

Drying techniques for preserving seaweed and other marine products as well as fruit and vegetables have been refined since the Jomon period (10,000-300 B.C.). There are two major categories of kanbutsu dried foods: those soaked in water and cooked or flavored and those used as is to blend with and bring out the flavors of other ingredients. Preparing dishes made with dried ingredients takes considerable time and effort as the ingredients must first be rehydrated.

Eminent examples of "natural foods," kanbutsu have long been prized for the particular flavors they acquire in the process of drying. Today, they are drawing renewed attention as healthy foods containing no chemical preservatives.

Konbu, a Treasure Trove of Minerals

In Japan, surrounded as it is by the sea, seaweed is available in abundance and has been a significant part of the national diet from ancient times. Today Japanese consume more seaweed than any other people in the world. A historical account describes how konbu (kelp) was among the gifts presented to the imperial court in 715. In the second half of the seventeenth century, after regular shipping routes were established along the Sea of Japan coast, konbu harvested in what was then the northernmost frontier of Hokkaido was available in sufficient supply that it became a staple of the diet in Kyoto, Osaka, Edo (Tokyo) and other cities.

Konbu, also called kobu, is a giant type of seaweed that can grow to twenty meters long. It is a multicellular algae containing chlorophyll and other pigments. Wakame and hijiki also fall under this category. Once all the konbu consumed was harvested from natural growth. In recent years, konbu cultivation methods have been developed, and the amount of cultivated konbu has increased. Of the total 137,000 tons harvested annually, 20 to 30 percent is from konbu farms.

Dried konbu produced for sale is prepared by first cutting off the roots and then spreading the fronds to dry. After a first stage of drying, the fronds are piled in sheds, then taken out and dried again. This process is repeated several times.

There are more than ten species of konbu, most of which grow in the seas off Hokkaido. Among them, four are most often used in cooking; ma-konbu, Rishiri konbu, Hidaka konbu, and Rausu konbu. All are different in shape, quality and taste and their uses in cooking are distinctive as well.

There are roughly two ways of using konbu: either as an ingredient in dashi stock or flavored and cooked as a main ingredient. Konbu dashi stock is used throughout the country. Of foods made from konbu itself, the most popular, mainly in Kansai (Osaka and vicinity), are tsukudani (soy sauce preserves), oboro kobu (shaved sheets of konbu) and tororo kobu (shredded konbu). Dishes that bring out the taste of konbu itself include kobumaki (konbu rolls) and matsumae-zuke pickles.

Konbu is extremely rich in minerals, calcium, iodine, vitamins A, B1, B2 and C and other nutrients.

Wakame and Hijiki: Affordable and Tasty

Like konbu, wakame is a species of kelp, but it grows only in seas where the current is warm. Harvestable in warm waters throughout the Japanese archipelago, wakame has been an important food since time immemorial. Rituals held even today on New Year’s at shrines across western Japan testify to wakame’s ancient role in Japan’s food culture.

Rich in high-quality protein, lipids and minerals, wakame also contains a good balance of vitamins A, B1, B2 and C.

The best-known wakame species are Naruto wakame, produced in Tokushima Prefecture, and Nanbu wakame, harvested in Iwate and Miyagi Prefectures. The drying technique using ash for Naruto wakame is said to have been invented around 1845. Harvested wakame is sprinkled with fern or rice straw ash before being laid out to dry. It is then washed with water and dried again. This method proved an effective preservation technique.

The volume of wakame consumed in Japan is over ten times that of konbu. A popular ingredient of daily meals, wakame, either salt-preserved or dried, is widely marketed as an ingredient of miso soup or vinegared fresh vegetables.

Another warm-current seaweed that is a familiar ingredient of household cooking is hijiki. Hijiki is a perennial seaweed that germinates every year for seven to eight years, attaching itself to rocks along the coastline. Its texture is hard, so hijiki processed for household use is first steamed and then dried in the sun. Containing much iodine and calcium, it is highly nutritious. Hijiki-no-nitsuke (hijiki seasoned with soy sauce and mirin, or sweet cooking sake, and complimented by strips of carrot and other ingredients) is a frequent feature of home cooking. Both wakame and hijiki are low-priced and tasty kanbutsu that are important ingredients of the Japanese diet.

Co-authors' Profiles

Kazuyoshi Shitomi was born in Tokyo in 1925. He graduated from Waseda Jitsugyo Academy in 1943 and began working at Mantou, his family-run, Asakusa-based wholesale store specializing in kanbutsu dried foods. In 1965 he succeeded as head of the family. For about six years he contributed a series of articles to a cooking magazine based on visits to places throughout the country where kanbutsu products are made and has written and edited numerous other articles on dried foods. He is the author of Kanbutsu Nyumon [Introduction to Dried Foods].

Isao Kumakura was born in Tokyo in 1943. He taught at Tsukuba University from 1978 to 1992. Since then he has held the position of Professor of Japanese Culture at the National Museum of Ethnology, Osaka. Among his major publications are Tea in Japan and The History of Japanese Food.