Haru yo Koi is a Solanin side story which was published alongside the one shot Himawari in the artbook Ctrl+T, which is a must for anyone interested in Asano's art. There are both old arts from the works he had published until the moment (it was released in 2010, when Punpun was still ongoing, and there's a nice message in which he asks for support in this new path of his) and some new art which I hadn't seen until the moment. If you look for "inio asano ctrl+t" on Google you can find some of them.
You can also see the book on its entirety
in a page per page video with soothing music here: http://www.bilibili.com/video/av16356079/
Haru yo Koi or Awaiting Spring is a one-shot originally published in Ctrl+T, which is primarily an Inio Asano art book containing original art, a colored Punpun chapter, some interviews, some other bonus material, and two one-shots, this being one of them. This was also recently collected in the Toronto Comic Arts Festival 2018 exclusive "Solanin: An Epilogue" along with the new chapter #29 and a proper translation of this (as opposed to the awful fan translation that's online where they not only had poor grammar, but also got plot points completely wrong). The first time I read it, I had it sitting at a
6 because the fan translation was just so poor that I didn't even understand certain plot points, but upon reading the official translation, I loved it. The official translation gets the poetic phrasing of Asano's writing perfectly. The story in itself is fairly simple, but it gets an 8 because it does exactly what it was intended to do: show that life goes on, other people are living their lives independent of you and the people you know, and that the things you leave behind will be picked up by someone else. Asano manages to pack a lot of personality into these two characters given the small amount of pages he has to work with. Definitely worth checking out, but I'd recommend trying to find the official translation. Keep in mind this score is relative and dependent on the fact that this a one-shot, so I'm not judging it by the same standards as a full manga series, because that would make no sense.
/End of Haru yo Koi review/
And in case you are interested in the Solanin Epilogue chapter #29, since they were now collected together in the West, and since MAL does not yet have a listing for it, here is my review of that (obviously as an extra and not affecting my score of this listing). Message me if MAL does eventually make a listing for the epilogue.
I thought the epilogue was great. Much like Awaiting Spring, it achieves exactly what it means to achieve, and that is that time goes on, things change, and we must move forward. It is set about 10 years after the events of Solanin and mostly focuses on Meiko's life, but also shows where all the supporting characters have ended up. It continues the themes of the main story and puts a nice bow on the whole thing, all without invalidating or somehow souring the closure of the original ending. The most interesting thing about this chapter is seeing not only the characters' growth, but also Asano's growth as an artist. His art looks exponentially better here than it did in Solanin, with more realistic characters, better shading, and the use of his signature background technique. I thought it was clever to include this together with the one-shot which was done 5 years after Solanin and 5 years before the Epilogue, essentially showing the evolution of Asano's skill and techniques. One of my favorite things about this little book was the afterword, where Asano explains some of his reasoning behind the pivotal turning point in Solanin and reflects on his journey since then. It's hard to score one-shots, but this is easily a 10.