Some inventions are born of necessity while others arrive as a result of an individual having a Eureka! moment. The Kuru-Kuru Nabe is, to some degree, a mixture of both. The name is Japanese for "Round-Round Pot" and is highly descriptive. The Kuru-Kuru Nabe is, in essence, a self-stirring saucepan, and it was invented by a humble Japanese dentist.
Hideki Watanabe lives in Iyo, in south-west Japan. He invented the Kuru-Kuru Nabe after experimenting with dental plaster at his surgery. Sculpting the inside surface of the pot into a spiral design changes how the contents of the pot heat up in several different ways.
Firstly the contents stir themselves; as they warm up, the spiral sides direct the flow in a circular fashion. This movement makes the heating process more efficient, so water, for instance, boils faster. This has the potential for saving energy. The contents' movement also means foam or skin forms in the center, making it easier to skim any residue off the top during cooking. Lastly, the chances of the contents boiling over are greatly reduced.
The Kuru-Kuru Nabe uses basic thermodynamics, but it's a unique design that no one has previously thought of applying to cookware. This is one of those innovations that no one has an urgent need of, but which could actually take off in a big way. Experienced chefs could use it to speed up cooking times, while inexperienced chefs could use it to avoid dishes boiling over. Also, the increased energy-efficiency of the Kuru-Kuru Nabe means potentially lower bills and less demands being placed on fossil fuels.
Watanabe is currently seeking investment in order to put the Kuru-Kuru Nabe into production. The image above is of a prototype, with the spiral sides of the pot molded from dental plaster. It works, as is demonstrated in this video, but it clearly isn't ready for use by consumers. There are images on Watanabe's website of further prototypes with the spiral sides molded from metal, which would imply Watanabe is getting closer to reaching his goal of putting the Kuru-Kuru Nabe into production.