I am highly annoyed by fics that try to play the statutory card with Shinobu and Miyagi. I checked. They’re fully legal. Shinobu’s 18 when he confronts Miyagi, safely putting him a year above Japan’s age of consent for adult relationships. Even by American or some European standards(I’ve read a lot of British writers in this fandom), it’s fully legal. It’s awkward, because hey, that’s the son of your boss, not to mention your ex-wife’s brother. And he was almost your student until he was convinced to test for a more prestigious university. But it is fully legal.