I suspect that if this had been one of my first manga, I would've liked it a lot more. Unfortunately for Dash!, there are a lot of beautiful, satisfying, thoughtfully constructed books out there that left this one feeling flat and underdeveloped in comparison.
It's composed of two separate stories, splitting the book in half. Couple 1 has three chapters, followed by three for Couple 2, with a bonus chapter about the first couple.
Dash! and the cover art is for that first section, about a guy who comes to a school specifically to spar and drool after his extraordinary judo senpai, Saitou. There are some interesting elements; Akimoto is initially disappointed because Saitou rarely comes to practice and doesn't demonstrate any of the exceptional ability that he'd shown in previous tournaments. Saitou uses Akimoto as an errand boy and generally presents himself as arrogant, lazy, and disagreeable. Of course, there's always more to the story, and it turns out that Saitou was badly injured in an unspecified accident that left him with temporary paralysis of one side - which he's slowly working through, determined to get back to the sport he loves.
This could've been a fascinating setup, but it really isn't. We don't actually get to see much of Saitou's recovery, or to hear more than a brief blip of his side of the story - a quick spill of feelings that's supposed to make it seem like he and Akimoto have A Special Connection. In truth, the better couple here would've been Saitou and his childhood friend (and judo team captain) Oka. Akimoto...isn't particularly interesting, and other than his hero worship turning into accidental lustful thoughts, it's not even entirely clear why he likes Saitou.
Their relationship also suffers from the "I guess I'll be sorta gay, but only reluctantly for one person" trope; while anything that happens between them is explicitly consensual, it doesn't really seem like Saitou actually cares about Akimoto. I get more of an impression of him being depressed, at loose ends with his slow recovery, and wanting someone to care about him and to see him as special. So if Akimoto is going to show that kind of devotion, even if it veers into the uncomfortably physical, Saitou might as well take him up on the offer.
There's nothing really objectionable about this story, but it just isn't developed in any significant or memorable ways. Although we're seeing the story from Akimoto's POV, I feel no attachment to him and don't particularly feel like he deserves Saitou's love; he just hounds his senpai and gets upset that Saitou doesn't immediately fall for him and seems more comfortable and affectionate with Oka - his longtime friend.
While they talk about a "forever" type of relationship, this definitely doesn't feel like one that will last after Saitou graduates, goes to college, and gets back into judo. Akimoto needs to channel his obsessions elsewhere and focus on his own life for a while, but there's no space for that kind of internal exploration.
The second storyline is more interesting and pulled this book up from 2 stars. Here we have Taka-chan, a college student whose cousin, Yoshirou, unexpectedly comes to stay with him. They'd had a bond when they were kids - Yoshirou had adored him, and when Taka-chan's family moved away, he promised that he would still "always be on Yoshirou's side." While Taka-chan grew up and mostly forgot about his cousin, Yoshirou kept those words close to his heart and used them to motivate himself through a deeply lonely adolescence.
Some of the tropes from the first story carry over - I'm not sure how often high school or college aged guys kiss each other just as a joke or to mess with each other, but apparently this is something Natsume is really into, because it happens frequently. It seems like an easy way to get physical encounters on the page without actually dealing with the emotional upheaval that comes from confessions.
There is more of that in the Taka-chan/Yoshirou storyline, at least. While it remains unclear throughout how Taka-chan actually feels about his cousin - and whether he's straight - Yoshirou himself is a pretty interesting and definitely bisexual character. There's some gritty, sad stuff about how he took care of himself after his parents went overseas and essentially abandoned him, and his promiscuity and attachment issues make a lot of sense once we get to see more of his story.
One negative blip was Taka-chan deciding that Yoshirou's ex-boyfriend was "actually a good guy" because he said a few sad things after beating up Yoshirou in front of him. But that relationship isn't the focus of this story, and everything between Taka-chan and Yoshirou is pretty sweet and genuinely affectionate. It closes out on a fairly open note; the potential was much stronger here, and I wish this entire volume had been devoted to exploring their relationship.
That makes me a little hopeful for the other Natsume series that I'm going to try out...I was expecting to get a good sense from this volume of whether or not I'd love that one, but it's difficult to tell. Maybe with more room to explore the characters, those sparks of potential will have room to flare into something much more beautiful.
I'm also hoping that books from a better publisher will improve the experience; I hadn't realized that this one wasn't from SuBLime, but from something called "Digital Manga Publishing." The quality of both the paper and the translation seems lower - there are "it's" and "its" mistakes in the default "here's how to read manga" text at the back of the book, "senpai" was spelled "sempai," and I'm really wondering if some of the emotional depth in these stories was lost in a subpar translation.