If you had to give their relationship a name, what would it be? “Endo-kun’s Experiment Notes, Vol. 2” by Hayakawa Nojiko（ハヤカワノジコ）

We’re introducing “Endo-kun’s Experiment Notes, Vol. 2” from Taiyo Tosho, ihr Hertz Series!

The following is quoted from the back cover. This review does touch on the story’s content! If you just want a quick overview!! I’d be happy if you read only the red text and highlighted sections.

“We can’t stay like this forever…———”

Endo and Tsuda gradually become aware that they can’t stay the way they are forever. Yet when asked what their relationship truly is, they find themselves unable to give an answer.

What is needed to keep the two of them connected?

It’s still not enough. I want more.

The two of them can no longer hold back their feelings……

From the ihr Heatz Series “Endo-kun’s Experiment Notes, Vol. 2”

In striking contrastto the cover of Volume 1,the vivid use of color immediately draws you in

While Volume 1 featured cool blue tones that gave off a fresh, airy atmosphere, Volume 2 shifts to soft hues close to pale purple, creating an evocative cover that feels almost like morning and evening—utterly captivating. In Volume 1, there were fewer moments of direct interaction between the two, but in Volume 2, they begin to reach out to each other more actively, as if seeking reassurance in one another. Wanting to touch more with their hands, to gaze at each other with their own eyes—those desires are conveyed through carefully detailed panels,expressed in a way that invites you to read between the lines, drawing you even deeper into the world of this work. It’s so good. (＾＾)

Physically speaking, Tsuda is taller and has larger hands and features overall, so there’s a scene where Endo is gently framed between Tsuda’s two hands, his face held in place… and honestly…

It’s like he’s being stitched in place so he can’t move at all… absolute perfection!!!!!

It feels less like their bodies are fully coming together all at once, and more like they’re gradually aligning, piece by piece. The pace seems urgent, and yet it’s as if the timeline is deliberately kept from rushing ahead. That sense of impatience—so frustrating, and yet so good—is part of what makes it wonderful.

And then there’s Tsuda’s older brother, “Akira”

When it comes to the future, Tsuda has carried a bit of a complex since childhood toward his older brother—his longtime consideration-free rival. Watching his brother play music at a club house stirs up a complicated mix of admiration and jealousy. Then that very brother returns to their hometown and starts teasing Endo. His behavior alone is enough to make your nerves tingle, but paired with an unfamiliar restlessness, it leaves Endo confused as well— and yet, he ends up saying something that makes Tsuda’s heart skip a beat…! （It hurts…!!! I love it…!!!）

While feeling uncertain about their own futures, the two of them continue to search for what might be the best choice and move forward together. The final volume is filled with heartwarming moments and plenty of affectionate skinship—and I hope we can all keep watching over what lies ahead for them…!!