Responses
Ryuu probably asked one of his partners if they knew someone suitable, since he himself only chooses partners that aren't serious. So sensei is a friend of a friend, most likely
I guess that's a possibility. I just thought Ryuu would have picked someone in person to make sure it's a good person since it was Yuuto who asked.
Maybe I'm missing something but shouldn't the sensei and Ryuu already know each other since Yuuto asked Ryuu to find someone for Komatsu?