Milestone-Proposal:Rice Cookers

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Docket #:

This is a draft proposal, that has not yet been submitted. To submit this proposal, click on "Actions" in the toolbar above, then "Edit with form". At the bottom of the form, check the box that says "Submit this proposal to the IEEE History Committee for review. Only check this when the proposal is finished" and save the page.

To the proposer’s knowledge, is this achievement subject to litigation? No

Is the achievement you are proposing more than 25 years old? Yes

Is the achievement you are proposing within IEEE’s designated fields as defined by IEEE Bylaw I-104.11, namely: Engineering, Computer Sciences and Information Technology, Physical Sciences, Biological and Medical Sciences, Mathematics, Technical Communications, Education, Management, and Law and Policy. Yes

Did the achievement provide a meaningful benefit for humanity? Yes

Was it of at least regional importance? Yes

Has an IEEE Organizational Unit agreed to pay for the milestone plaque(s)? Yes

Has an IEEE Organizational Unit agreed to arrange the dedication ceremony? Yes

Has the IEEE Section in which the milestone is located agreed to take responsibility for the plaque after it is dedicated? Yes

Has the owner of the site agreed to have it designated as an IEEE Milestone? Yes

Year or range of years in which the achievement occurred:

1923, 1955

Title of the proposed milestone:

Commercialization of Electric Rice Cookers, 1923 and 1955

Plaque citation summarizing the achievement and its significance:

The world’s first ‘electric rice cooker’ and ‘automated rice cooker’ were released in 1923 and 1955 by Mitsubishi Electric Corporation and Toshiba Corporation, respectively. Each was aimed at a kitchen appliance for rice cooking, which consisted of a main pot, a cooking bowl, a heat source, and a thermostat. They contributed greatly to the spread of home electrification in postwar Japan.

In what IEEE section(s) does it reside?

Tokyo Section and Kansai Section

IEEE Organizational Unit(s) which have agreed to sponsor the Milestone:

IEEE Organizational Unit(s) paying for milestone plaque(s):

Unit: Tokyo Section
Senior Officer Name: Yoshiaki Nakano

IEEE Organizational Unit(s) arranging the dedication ceremony:

Unit: Tokyo Section
Senior Officer Name: Yoshiaki Nakano

IEEE section(s) monitoring the plaque(s):

IEEE Section: Tokyo Section
IEEE Section Chair name: Yoshiaki Nakano

Milestone proposer(s):

Proposer name: Isao Shirakawa
Proposer email: Proposer's email masked to public

Please note: your email address and contact information will be masked on the website for privacy reasons. Only IEEE History Center Staff will be able to view the email address.

Street address(es) and GPS coordinates of the intended milestone plaque site(s):

Describe briefly the intended site(s) of the milestone plaque(s). The intended site(s) must have a direct connection with the achievement (e.g. where developed, invented, tested, demonstrated, installed, or operated, etc.). A museum where a device or example of the technology is displayed, or the university where the inventor studied, are not, in themselves, sufficient connection for a milestone plaque.

Please give the address(es) of the plaque site(s) (GPS coordinates if you have them). Also please give the details of the mounting, i.e. on the outside of the building, in the ground floor entrance hall, on a plinth on the grounds, etc. If visitors to the plaque site will need to go through security, or make an appointment, please give the contact information visitors will need.

Are the original buildings extant?

Details of the plaque mounting:

How is the site protected/secured, and in what ways is it accessible to the public?

Who is the present owner of the site(s)?

Mr. Takeshi Sugiyama, President and CEO, Mitsubishi Electric Corporation, and Mr. Nobuaki Kurumatani, President and CEO, Toshiba Corporation

What is the historical significance of the work (its technological, scientific, or social importance)?

The major historical significance concerning ‘electric rice cooker’ and ‘automated rice cooker’ is briefed in what follows.

1. Historical Background of Commercializing both ‘Electric Rice Cooker’ and ‘Automatic Rice Cooker’

In the past the rice cookers were operated by non-automated dedicated rice-cooking utensils, whereas at present they are by automated electric/gas rice cookers. The world’s first ‘electric rice cooker’ [1] and ‘automated electric rice cooker’, or simply ‘automated rice cooker’ [2], were released in 1923 and 1955 by Mitsubishi Electric Corporation and Toshiba Corporation, respectively [3]. As for the former, its commercialization was accomplished in the year when the Great Earthquake of 1923 occurred, and it was used restrictedly in shipping. On the other hand, as for the latter, it was the first commercially successful rice cooker put on the market, and its commercialization contributed remarkably to the rapid spread of home electrification in postwar Japan.

2. History of the Commercialization of Electric Rice Cookers

The ‘electric rice cooker’ developed in 1923 by Mitsubishi was composed of a main pot, an inner cooking bowl to hold rice and water, and an electric heating element. The bowl filled with rice and water was heated until the water reached to the boiling point. Since this rice cooker did not yet have an automatic turn-off facility, it had to be made turned off when the water in the bowl boiled off. Thus, in around 1930 Mitsubishi managed to attach an automatic turn-off facility to the rice cooker so that the cooker could be turned off when the temperature of water in the bowl rose above the boiling point. Here, it should be added that this cooker was still used in shipping [4].

3. History of the Commercialization of Automated Rice Cookers

The ‘automated rice cooker’ developed in 1955 by Toshiba using a double-chamber indirect rice cooking method, was the first successful rice cooker for home use. Rice was placed into a rice pot, and water into a surrounding container. When the water in the outer container boiled off, the temperature of the rice pot rose rapidly. A bimetallic thermostat then activated, and automatically turned off the heater to prevent burning of the cooked rice. The commercialization of this automated rice cooker soon led Toshiba to produce 200,000 units per month for the Japanese market. Four years later, rice cookers could be found in half of Japanese homes [3].

What obstacles (technical, political, geographic) needed to be overcome?

The development phase of electric rice cookers encountered a number of obstacles as outlined below.

1. Obstacles to the Development of Electric Rice Cookers

The ‘electric rice cooker’ was developed by Mitsubishi, using the simple concept of heating the rice to cook and turning off the heater when the temperature rose to a certain point. This method, however, was influenced by the variation of room temperature so severely that under-cooked rice was frequently produced. Thus, in the early development phase, many makers continued to experience failures in their ongoing trial-and-error approaches [3].

2. Obstacles to the Commercialization of Automated Rice Cooker

Toshiba’s ‘automated rice cooker’ took more time for rice cooking, and also consumed more electricity than Mitsubishi’s ‘electric rice cooker’. In addition, since it had no keep-warm function, the cooked rice had to be moved to heat-insulated serving containers. Hence, the usage of this cooker began to be phased out in the late 1950s, until in 1965 Zojirushi Corporation embarked on assembling a novel rice cooker with a keep-warm facility, using a semiconductor heat regulator. The production of new cookers soon grew to 2,000,000 units per year [4].

What features set this work apart from similar achievements?

Both ‘electric rice cooker’ and ‘automated rice cooker’ had distinctive features as summarized below.

1. Unique Development of the Electric Rice Cooker

In old times the rice cookers relied on non-automated dedicated rice-cooking utensils, which have an ancient history (e.g. a ceramic rice cooker dated to 1250 BC is on display in the British Museum [3]). Mitsubishi Corporation was the first company in the world that released an ‘electric rice cooker’. The Mitsubishi product was an aluminum pot with a heating coil inside. Even after Mitsubishi released this rice cooker in 1923, they were still unable to realize a turn-off facility to attach it, resulting in constant monitoring during cooking. Hence, Mitsubishi became very eager to seek the turn-off function, until in the early 1930s they managed to succeed in realizing a turn-off facility attached to the rice cooker. Here, it should be noted that the new cookers with a turn-off facility were still used in shipping [4].

2. Rice Cookers with the Turn-Off Facility

In 1955 the first commercially successful ‘automated rice cooker’ was placed on the market by Toshiba, using a double-chamber indirect rice cooking method. Although this rice cooker had an automatic turn-off function, it did not yet have a keep-warm function, and the cooked rice cooled down so quickly that it was often necessary to move the cooked rice to serving containers. Thus, even though the production volume grew to 200,000 units per month, its market began to be phased down in the late 1950s, and the rice cooker with a keep-warm function was expected as a next commodity. In 1965 Zojirushi embarked on developing a novel rice cooker with a keep-warm facility.

3. Subsequent Developments of Rice Cookers

3. Subsequent Developments of Rice Cookers

Since the 1980s, higher-end electric rice cookers had used microprocessors to control the cooking process in more detail. In addition, since the 1990s, Japanese makers had been attempting to compete by seeking a niche in models with added values by increasing the number of features of their products. Thus, more advanced cookers would appear, adopting novel methodologies for more detailed temperature control, induction rather than resistive heating, steaming trays for other foods, etc.

Supporting texts and citations to establish the dates, location, and importance of the achievement: Minimum of five (5), but as many as needed to support the milestone, such as patents, contemporary newspaper articles, journal articles, or chapters in scholarly books. 'Scholarly' is defined as peer-reviewed, with references, and published. You must supply the texts or excerpts themselves, not just the references. At least one of the references must be from a scholarly book or journal article. All supporting materials must be in English, or accompanied by an English translation.

[1] (in Japanese)

[2] (in Japanese)


[4]炊飯器 (in Japanese)

Supporting materials (supported formats: GIF, JPEG, PNG, PDF, DOC): All supporting materials must be in English, or if not in English, accompanied by an English translation. You must supply the texts or excerpts themselves, not just the references. For documents that are copyright-encumbered, or which you do not have rights to post, email the documents themselves to Please see the Milestone Program Guidelines for more information.

Please email a jpeg or PDF a letter in English, or with English translation, from the site owner(s) giving permission to place IEEE milestone plaque on the property, and a letter (or forwarded email) from the appropriate Section Chair supporting the Milestone application to with the subject line "Attention: Milestone Administrator." Note that there are multiple texts of the letter depending on whether an IEEE organizational unit other than the section will be paying for the plaque(s).