This is exactly why I think Koyama was a mistake. He shouldn't have even existed. He represents nothing and adds…
(I can't read the comment that you're replying to, so I don't know the context, but...)
I thought Koyama was a great addition to the story. Because of Koyama Hira stands up for himself for the first time. He actually raises his voice in that conversation after Koyama confesses. I thought that was a pivotal moment in his character development. Aside from that, I think Koyama humanizes Hira. We see that he's actually able to have a friend without being wholly immersed in that inferiority complex. I think this shows his growth too; it contributes to why Hira ultimately is able to see that he is "worthy" of Kiyoi's affection.
I thought Koyama was a great addition to the story. Because of Koyama Hira stands up for himself for the first time. He actually raises his voice in that conversation after Koyama confesses. I thought that was a pivotal moment in his character development.
Aside from that, I think Koyama humanizes Hira. We see that he's actually able to have a friend without being wholly immersed in that inferiority complex. I think this shows his growth too; it contributes to why Hira ultimately is able to see that he is "worthy" of Kiyoi's affection.