I hope that this review offers something of value to both people who have and who haven't yet watched the anime, though if you're very spoiler-averse when it comes to structure, maybe don't read past the first picture. Actual spoilers will be clearly marked. I’ll be focusing mainly on the story’s themes and symbolism rather than its technical execution.

The story of Rainbow takes us to post-war Japan in the 1950s, specifically to a disciplinary school that is essentially a glorified juvenile prison, where we arrive alongside our protagonists at the start of the series. Before diving into the narrative itself, it’s worth briefly looking at what this setting looked like in real life. Post-war Japan was a wreck: the dead and dying people, bombed-out cities, scarce resources, and a generation of kids forced into survival mode long before adulthood. Juvenile crime spiked roughly 160% in the immediate postwar years—not because teens suddenly became evil, but because the entire country was traumatized, demoralized and starving, and this often forced the most vulnerable groups of people to fend for themselves.

This is the world Rainbow drops us into: not a stylized prison fantasy, but a grim reflection of an era where kids were treated as disposable, and the anime doesn’t soften this backdrop. It leans into it and builds its themes directly from it, as we follow our seven protagonists through a meditation on human bonds forged under hardship. It functions almost as a modern fable, with the school serving not only as a setting but as a crucible preparing them for the real story: how do people respond to systemic violence, abuse, and injustice? How do people shaped by trauma navigate a world that refuses to hand out happy endings?

The show treats those questions very seriously, and tackles trauma and injustice with real emotional weight, but not always with real-world logic. Some characters function more as symbols than people, and certain outcomes favor thematic clarity over realism (which I will expand on within a spoiler). This isn’t a flaw, just a stylistic choice, but it's worth noting if you expect a fully grounded and/or nihilistic depiction of post-war hardship.

However, despite its moments of symbolic catharsis and idealism, Rainbow avoids offering easy solutions or neat resolutions, not for the sake of prolonged suffering but to reinforce another important message to both the boys and the audience: life rarely goes the way you want, but that shouldn’t stop you from pursuing it anyway. One lost opportunity might lead to another you never expected, but as long as you keep moving, you’ll end up somewhere.
In my opinion, this is one of the most realistically positive messages the series conveys. Life doesn’t hand out tidy victories, and Rainbow doesn’t pretend otherwise. But it insists that even in brutal circumstances, compassion can become a lifeline, and even broken trees might bloom again.

Since Rainbow builds its themes through the people shaped by its world, I also want to address the boys themselves—the symbolic ‘rainbow’ the story revolves around. All of them are lovable despite their flaws and form the emotional core of Rainbow, functioning both as compelling individuals and as a cohesive unit. While the story is at its strongest when they’re together, each has unique traits and personalities. They don’t all share the same level of complexity, but they all feel authentically shaped by their backgrounds and trauma. Even though the anime doesn’t give all of them equal screentime, their distinct voices and genuine bonds make them very engaging to follow.
I won’t be diving into all of the major characters, but I’d like to share a few thoughts on some of them:

Lastly, I also want to mention the animation and sound, in the sense that the presentation of the anime does a good job of reinforcing both the themes and the symbolism of the story. Many scenes take place in bleak, monotone environments, which makes the stylized manga-panel inserts—washed in rainbow gradients to highlight emotionally or morally charged moments—stand out even more as snapshots of both the good and the bad that shape the characters. The narration that accompanies these scenes can come across as overly sentimental at times, bordering on overdramatizing moments that are already dramatic on their own, but it still fits the tone of the series and enhances its almost allegorical quality.

Personally, I had a great time with the anime, and found its structure and presentation very interesting for the kind of story that it is. I think that if you appreciate works like Grave of the Fireflies or even Goodnight Punpun for their unflinching portrayal of tragedy and nihilistic realism, Rainbow might feel too overly idealistic, but if you found those works to be too emotionally draining or challenging, this story enables a much more digestible approach to the darker aspects of life—not by softening the brutality the boys endure, but by insisting that compassion can create hope strong enough to sustain people even in a broken world. The series can anger you and devastate you, but unlike purely nihilistic works, it still leaves you believing in the possibility of something better.