Had to read this last, as it was unavailable in the library when I read the others... so it felt like going back in time a bit.
Nevertheless, this episode of Gen's story explains how Ryuta and him become friends, and, surprisingly, foreshadows two important elements in the story: the painting and the very clear metaphor of the wheat.
It is one of the more powerful chapters of the story, as the bomb is still very recent and the plight pof the hibakusha (bomb survivors) is quite clearly introduced to the story here.
There's compassion, friendship love and optimism in the darkest of circumstances, so it is an uplifting story.
Perhaps the only aspect of it that hasn't aged very well is the recurrence of physical violence as a gag. It seems to call back to slapstick comedy, and sometimes it does work, but it feels out of place in a book with such a deeply pacifist message.
Otherwise a very remarkable and fun read. :)