I think it was interesting.
I'm curious if the 10 chapters were an imposed constraint, or if that was the author's plan from the get-go, or if it was implemented after-the-fact and the original intention was for a larger count / longer duration. I think the answer to that, would inform more of how I interpret the work we are given, but I don't believe it necessary, given the work we're given.
I do think that getting a bit more detail about Hana would have maybe helped round out her perspective, but I feel satisfied in how she was portrayed through the lens of Hikaru. Hikaru's recollection of Hana was the key--she'd built Hana up into this almost megalithic presence, solely through her perception of the girl, and then the woman. Every instance of contact Hana would have with the world, would be burned into Hikaru's mind. To the point that she turned to photography in Hana's absence, simply to try and record the spaces she once filled.
Even her absence continued to hold immense weight for Hikaru--and as much as she loved Harutaka, Minami said it pretty aptly in chapter 9. She states how First Loves are meant to be left in the past; how she believes that people will choose the present in front of them. But her own admission speaks to the folly that she, that Takuhara, that Hikaru herself succumbs to: that she should have never told her friend that Hana was returning, precisely because of the gravity that woman holds over Hikaru's existence.
And that is very much shown and implied, more than explicitly stated, though I would argue it's the most concrete fact iterated throughout the series. Hana means everything to Hikaru, and no amount of time or distance would dilute that truth. Takuhara filled in the intervening years, but from the moment he sees Hikaru's shift in demeanor upon the first whisperings of someone returning from her past, even he seemed to immediately realize that a shift was taking place.
And, I suspect that was part of his understanding, and his grace in letting her go as he did. Ao was outraged, taking up the mantle of anger and indignation for them both, but he wasn't close to Hikaru like Takuhara was--and because Takuhara loved her so much, I would argue he could see the shift in her, as gravity tilted, and she was inexorably drawn from his side to Hana's. It seemed like he was in the process of coming to terms with Hikaru leaving, even before waking up to the letter on the table. Sure, it hit him when he finally read it--but that general minimized reaction from him coupled with the moments we see him throughout the series up to that point make me think that he knew there was an expiration date on his marriage and on Hikaru remaining in his life.
And...there are some relationships like that. And not all of them are healthy, or good, or "accepted" by those people who surround the ones at the center.
And I think the point here, is that Hikaru is not meant to be "a good person". Just "a person", and those are always messy and rife with marred edges and scars.
But I do think that the point being made is that she chose her happiness, and the one that would leave her with less regret. It might look wrong to people sitting on the outside--certainly the case for Ao and for Minami--but the story is Hikaru's, first and foremost. It was about her finding the place where she felt most at peace and the most centered, and what it would cost to achieve that.
I'm glad I read it. I certainly didn't expect a conventionally happy ending, but I think what we were given satisfied the premise and the trajectories of each character.
And, as far as this one goes, I saw who was TL'ing it and sorta knew I was going to be in for something specific(ish), so.
Thanks for working on this one and bringing it to us.