Since the 1980s, electric rice cookers were manufactured in China and Korea, who focused on simple feature models because of the market trend which regarded the price competition to be more important than rich features.For modern home rice cookers, the smallest single-person model cooks 1 rice cup (180 ml), whereas large models can cook 10 cups. Commercial models can cook 20 or more cups. As a possible source of confusion, model specifications and names may list either cooked or uncooked capacity. Rice roughly doubles in size during cooking; therefore, a 10 cup (uncooked) rice cooker can produce up to 20 cups of cooked rice.
Some visitors to Japan desired to buy Japanese domestic models as souvenirs, due to their ability to produce better tasting cooked rice and the multiple features. Since the Japanese domestic models use 100 volts only, they cannot be used in most other countries without adapters and power converters. In Akihabara Electric Town, various models that are modified to be able to operate under 110 V/220 V-240 V are sold in boxes that are labeled with English. A few rice cooker makers produce export models for use abroad.So you can buy the best rice cooker in Japan.
In 1937 the Japanese Imperial Army sanctioned an Type97 automobile-kitchen equipped with a primitive rice cooker. The rice cooker was a rectangular wooden box with two electrodes attached to opposite ends. To cook the rice, the box was filled with washed rice and water, and then a current was applied. This caused the water to boil. When the rice was cooked, the reduction of the water caused an increase in resistance and reduced the heat, then it automatically became a stay-warm state. This method, however, was not suitable for different water qualities or degrees of rice washing and as such varied the amount of heat produced and the end results. The best rice in Japan cooker was suitable for home cooking.