"Premonition of love". Oh, there, I translated it.
It's not untranslatable. It's just not a popular culture thing anywhere except Japan.
Sure, it's different from "love at first sight" because you feel you will love them, not that you already do.
Personally, sounds a lot like "lust" or just "interest" to me.
I think there are some characteristics that will induce koi no yokan:
- jishin ((quiet?) confidence)
- ii kanji (feeling of good)
- yasashii kanji (feeling of gentleness -- maybe something like "has empathy")
- atama ga ii (smart). This is only popular in certain circles and is more typically valued by women in men than the other way) -- most Japanese men seem. It to want their wives to be smarter than they are (although a small portion do).
- a few more?
I just want to express how difficult it was to write the above. I started in English, but then realized that it was only accurate if I used Japanese. The translations are rough, and they are things that strike me as fairly easy to understand in a Japanese context for me, but less so in an English/US context -- maybe due to a wider range of values held in the latter.
On a personal level, a woman I dated when I was younger when I lived in Japan had koi no yokan for me. I regret not marrying her -- she knew us better than I did.
I would love to hear other people's additions and opinions on this matter.
I wouldn't take advice from the Japanese on relationships.