FWIW I never heard of that either, despite living in Japan on and off for a couple of years, marrying a Japanese woman, and being decent at Japanese
My guess is that it's just a 1960s meme that's fallen out of use
Actually, I've never seen or heard of any of the butter-related stuff.. Maybe those butter tools are a regional thing, or they're relatively unknown. I've never seen them on TV, and I couldn't find any butter dishes for sale when I was looking for one in Tokyo, so I ended up having to use a plastic box from the dollar store.
My in-laws were furious when I kept hiding butter in a tray outside of the fridge so it'd stay soft, and all their friends agreed with them that I was being a crazy foreign fool
Was it salted or unsalted butter? From experience it's mostly unsalted in Japan which shouldn't be left outside of the fridge.. Unless it's a big house and you go through it in a few days.
