At some hi-tech restaurants, customers can place orders via touch screens. (Kura Corp.)

Robots Prove Adept at Shaping Rice
November 26, 2001

Sushi is known throughout the world as the quintessential Japanese food. Conveyor-belt sushi restaurants, as popular as ever in Japan, have spread as far and wide as Paris, London, Amsterdam, and New York. Some pioneering restaurants in Japan have turned to technological innovation as a means of pleasing customers and producing profits.

Rice: The Lifeblood of Sushi
Shari, the rice portion of sushi, is a slightly compressed, cylindrical bed of rice that fits snugly in a softly clenched hand. A touch of wasabi and a piece of freshly sliced fish on top rounds out a typical piece of sushi, as known and enjoyed in Japan and around the world. Great sushi is a result of the quality of the shari and the freshness of the fish. Since the beginning of sushi, shari has traditionally been prepared by hand; several years of training are usually required in order to make it properly. Recently, however, the appearance of robots that can prepare shari in place of humans has been grabbing attention.

Technology and Tradition
The quality of sushi made by robots is comparable to that achieved by veteran chefs. Sushi robots are primarily used at kaiten-zushi (conveyor-belt sushi) restaurants. These commonly feature an elliptical counter around which customers sit. A conveyor belt revolves around the perimeter of the counter, bringing forth a colorful variety of sushi, usually two or three pieces per plate. As the sushi plates pass by, customers simply reach out and select their favorites. Kaiten-zushi tend to be less expensive than traditional sushi restaurants, where the chef takes the customers' orders and directly serves the sushi across the counter.

liquid-crystal panel
Using this touch screen, customers can order not only sushi but desserts and drinks as well. (Kura Corp.)
The difficulty of getting a robot to make shari lay in the task of consistently shaping each piece to a fixed size and texture that, when eaten, causes the pleasant sensation of gently expanding in the mouth. Sushi robots, which automate the shari-making process and are able to produce at two to three times the speed of veteran chefs, produce quite good shari. However, before the sushi is presented to customers, a chef applies the finishing touches by layering the sliced fish and adjusting the shape with his own hand. Sushi robots may be good, but it seems that in the end making tasty sushi still requires the handiwork of a human expert.

The sushi conveyor belt, a Japanese invention, has also undergone some hi-tech innovations. A new type of conveyor belt invented by Ishino Works Corp. (site in Japanese only) features a transparent plastic cover along its whole length to help preserve the freshness of the sushi and protect it from dust. Kita Nihon Kako Corp. makes a conveyor belt that has no chains or holes, making it easy to clean and more sanitary. Japan Crescent Co. has developed a more powerful conveyor belt that can circulate larger plates of food, such as tempura and desserts, in addition to the smaller plates of sushi.

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Some shops have even installed touch screens to enable their customers to order the sushi they want. Kura Corp. (site in Japanese only) and Sega Corp. have jointly developed such a system. Customers make their selections by touching a liquid-crystal panel that displays computer-animated images of the various kinds of fish available swimming around. Once they place their order, customers are treated to a voiced explanation of the type of fish that will shortly adorn their plates. This system is especially popular among children.

Interest from Abroad
Sushi robots were first introduced in around 1981 but were initially kept tucked away in the back kitchens and out of sight, due to concern that customers would lose their appetites if they saw shari being shaped by a metal contraption. Recently, however, a new type designed in the shape of a traditional rice tub has been introduced. Shari is shaped inside the tub by a screw-shaped blade. Once a piece of shari is removed by the sushi chef, the next piece is made right away.

The kaiten-zushi business model, which offers customers healthy sushi at a reasonable cost, has begun spreading to other Asian countries and to the West. It takes many years to become a good sushi chef, however, including mastering how to shape shari, so achieving high quality in countries that are new to sushi is difficult. Sushi robots may be the answer to this problem, as they could enable sushi lovers anywhere to enjoy shari of broadly the same quality found in conveyor-belt sushi restaurants in Japan. This may help to explain why inquiries from restaurant owners overseas about these new sushi robots have been on the increase over the last couple years.

Copyright (c) 2001 Japan Information Network. Edited by Japan Echo Inc. based on domestic Japanese news sources. Articles presented here are offered for reference purposes and do not necessarily represent the policy or views of the Japanese Government.

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