Why is a thermos called a 魔法瓶? I just stumbled across this word today, and was baffled to find that a thermos is a "magic bottle"? What reason is there for the kanji chosen? Was it a decision by a company who introduced/manufactured the first thermoses in Japan?

We had not understood the reason why a thermos is called , but Mr.Awazu, who was a director of memorial house, found out the reason a few years ago.

He found out a oldest newspaper article which was written the word at October 11th in 1907. The article said that in his interview about hunting, a person referred to the high performance and convenience of a thermos, which had been just imported to Japan at that time, and quoted (Magic Bottle) in Aesop’s Fable. His words were used in the oldest advertisement of a thermos in Japan and he was decided to be the author of .

However (Magic Bottle) isn't in Aesop’s Fable and it seems to be his misunderstanding.

This is the source. <