"Of course," Koumyou smiles over at his son, drifting a bit further out himself, treading water with ease. "That's part of what I mean when I say 'you made it'. You were always so strong, you know?"

He'd known his kid would make it, one way or another. But it's still something else entirely to see it for himself!

"...I could teach you here on the train, if you like."

Genjo might not know the reasons, but he surely remembers that Koumyou doesn't like to teach. In general. And yet, he's making the offer, which is a huge step he'd never been able to face before.