My grandparents had this Okama, and they used to cook rice with it when I was little.
These are the picture of Okama cooked with frame.
And after a while, I remember my parents bought Gasu-kama which uses Gas. In UK, some Japanese restaurants still use this type of rice cookers. The quality of rice is better cooking with this type of rice cooker than electric rice cookers.
I have us
ed this type of rice cooker at the restaurant in London.
This type is an industrial use for rice cooking.
This is the latest type of rice cooker we use in Japan nowadays.
It is electric, and has got a timer so that we could set the time we would like the rice ready and we set it usually for breakfast and dinner time, and expensive type of rice cookers cook brown rice etc.
I have seen this type of rice cooker in the shop in China town.