In Episode 2, Kaoru and Sentaro accompany Ritsuko back to the record store, just in time to catch Jun. After a moment, Ritsuko's dad joins them and the three start to jam. While they play, Sentaro urges Kaoru to jump in on the piano, and after some coaxing, manages him to not only do just that, but to loosen up a bit and have fun with it. Its nice to see their friendship progressing like this. Before, they could hardly stand each other, and for Sentaro to invite "Richie" to jam with him and his friends is a big step for him, considering how much he disliked Kaoru's classical background and "only jazz" was allowed in the basement.
The end of episode 7, when Kaoru stops being mad at Sentarou and they play a medley of songs together.
The episode when Kaoru meets his mother. At the end, he promises to see her again and leaves her some music to practice so they can perform together when they reunite. She starts crying when he gets on the train. When she says she is sorry, he shakes his head as if to say he doesn't blame her for what happened.
In the manga, he sees her again. She has memorized the song and is learning how to read and write. He starts to visit her regularly while living in Tokyo.
Kaoru comforting Sentarou in the last episode.
Sentarou's uncle coming back home and showing him he really does care for him as if he were his own biological child. Sentarou cherishes the gift he was given years later.
The reunion after the Time Skip. Kaoru finally finds out where Sentarou is and starts playing their song in the church, then Sen joins him.
When Jun leaves by train he says goodbye to Yurika, but at the last second he pulls her onto the train with him.