How about a clock?
Now, I understand that in 1955 the required components might have been deemed too expensive, or actually the problem is more complex than that. This article is so poorly written. Like almost everything I've read in the last 20 years from IEEE Spectrum.
How would the rice cooker know when to start the clock? It needs to be started only after the water reaches a boil.
From the article: > Fumiko found that heating the water and rice to a boil and then cooking for exactly 20 minutes produced consistently good results.
That knowledge about the ideal timespan of 20 min seems to be completely irrelevant to the implemented solution.
Partially. They also mentioned that it was generally believed that you needed to vary the temperature during cooking to get fluffy rice. Fumiko's discovery is just as much about the fact that you can use a straight boil the whole time as it is about the duration.