Hoshino Gen’s ‘Fushigi’: Why the 2021 Rom-Com Theme Hits Harder Three Years Later

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Hoshino Gen released Fushigi on April 27, 2021. For a long time most fans probably filed it away as “the theme song for that TBS rom-com” and moved on. Three, now almost four years later, the shape of this track has quietly changed. ‘Fushigi’ doesn’t perform the flutter of a crush — it records the physics of one. What we heard in 2021 as a functional drama theme now reads differently, especially when you play it alongside everything he’s done since.

At the time, it landed as the follow-up to Sozo — another digital single, dropped mid-pandemic. Looking back, this feels like the song where Hoshino Gen, standing on the biggest possible stage (a prime-time TBS drama theme), quietly rewired the design principles of his own pop music.

Key facts

• Hoshino Gen’s Fushigi was released as a digital single on April 27, 2021.
• It was written as the theme song for the TBS Tuesday drama Kikazaru Koi ni wa Riyuu ga Atte.
• Co-arrangement by mabanua, drums by Shun Ishiwaka, bass by Hama Okamoto, guitar by Ryosuke Nagaoka — the familiar core of Hoshino’s studio circle.
• From April 2023, the song was used as the Kirin Beer “Tanrei Green Label” CM song, with Hoshino himself appearing in the ad performing a solo acoustic version.
• A physical release followed in June as the double A-side single Fushigi / Sozo.

The setup: a drama theme that arrived a week after it aired

Start with the facts. Hoshino was announced as the theme artist for Kikazaru Koi ni wa Riyuu ga Atte on March 30, 2021. The title Fushigi was revealed when the drama premiered on April 20, and the digital single dropped just a week later, on April 27. Alongside its predecessor Sozo, it was framed as a track that strongly signalled a new stage in his catalogue. Song debuts on TV, hits streaming seven days later — that turnaround is still worth pausing on as a piece of promo design.

What’s interesting is how Hoshino himself talks about getting the offer. Director Tsukahara — who he’d worked with on MIU404 — told him during that shoot that he was next going to direct a “kyun-kyun” (heart-flutter) style TBS Tuesday drama. Hoshino says he was genuinely surprised. Tsukahara had done Chuugaku Seinikki and leaned toward serious material rather than rom-com, so the pivot felt unexpected to him. That word — unexpected — sits underneath the whole song. He wasn’t going to write the standard rom-com theme with the standard rom-com face.

The other bit of background worth knowing: to lock down his own version of what “kyun” actually means, he kept re-watching the Kyoto Animation shows Chuunibyou demo Koi ga Shitai! and Tamako Market, returning to them whenever he hit a wall in the studio. That detail hits differently on a re-listen. The theme for a live-action romance was being built with Kyoto Animation as its emotional reference point. That’s basically the mood board — late at night, alone in your room, hitting play. That specific grain of feeling.

Reading the sound: Ishiwaka, mabanua, and five vintage synths

For anyone who listens with a sound-nerd ear, the credits do most of the talking. Hoshino handles vocals, chorus, Minimoog, Prophet-5, DX-7, piano and programming. Shun Ishiwaka plays drums. Hama Okamoto is on electric bass. Yasuhiro Sakurada covers DX-7, Juno-6, piano and Rhodes. Ryosuke Nagaoka is on electric guitar and chorus. mabanua contributes Minimoog, Prophet-5 and programming.

The way the synths are stacked is the thing. Analogue and early-digital hardware from the ’70s and ’80s, laid gently underneath live piano, live drums, live guitar, live bass. The blend is strange. It never sounds like a “synth-forward” record. Listen closely to the intro and you can hear keyboard particles spreading out like ripples on water. This isn’t an arrangement built on outlines. It’s built on humidity.

Ishiwaka’s drums enter differently from earlier Hoshino records too. Less about riding a dance grid, more about manipulating the weight of the beat. The BPM isn’t fast. And yet the song feels like it’s moving. That illusion comes from the way Ishiwaka places his fills locking into mabanua’s programming — mabanua, following on from Sozo, co-arranges here too and does a huge amount of the world-building. The line between live drums and programmed beats is being blurred on purpose.

Then there’s Nagaoka’s guitar. He softens the edges of a chord rather than nailing it down. Here he doesn’t stab at the harmony — he sets it down. When Hoshino’s falsetto lands on top, there are moments where the actual subject of the song stops being the vocal and becomes the air around it. Hama Okamoto’s bass sits back into that same logic, less about drive, more about carving out a place for the low end to live. Nothing flashy. Pull him out and the song collapses.

Three things to listen for

• The intro into the first verse — how the synths bleed into the acoustic piano. A mix that refuses hard lines.
• The pre-chorus into the chorus — where Ishiwaka’s snare sits. It never rushes, but it leans forward.
• Second half of the track — the backing vocals (Nagaoka and Hoshino) wrapping around the melody. The rom-com “kyun” isn’t in the lyric here. It’s in that harmony.

A quiet pivot: this was the turning point

It was hard to see at the time, but put Fushigi next to what Hoshino has released since and the texture is obviously different. He shifted from music designed to make you dance, to music designed to sync up your breathing. That’s the biggest thing that only becomes visible in hindsight.

His mainstream image was built by Koi in 2016, and by the YELLOW DANCER to POP VIRUS run — dance-music muscle, four-on-the-floor pleasure, big horns and strings, pop that moved your body. Fushigi plants its feet somewhere else. Live-band feel, synths treated like they’re underwater, a vocal that pulls back into falsetto. Precisely because the drama is a rom-com, the song refuses to perform. That distance is what felt new.

Hoshino has said, in his own words, that he tried to properly turn into a song what he himself actually thinks love and romance are. That intention is what pays off in retrospect. From here on, he stopped hesitating about bringing something too personal onto a mass-audience stage like a prime-time drama slot. Fushigi reads, in hindsight, as the first door he opened in that direction — not a giddy jump-in-the-air flutter, but a small wave breaking somewhere behind the ribs. Picking that register for a rom-com theme was a genuinely brave call.

When does the song actually work?

Something long-time fans might just nod at: Fushigi feels engineered as a song you play alone, late at night. Which is a strange thing to say about a rom-com theme.

If you were watching the drama live at 10pm on a Tuesday in 2021, cue it up at that same hour now and the outline shifts. In the daytime, this track sounds a little thin. At night, with the lights low and household noise gone, the humidity of the synths comes up. The reverb tail on those intro keys, the ring-out on Ishiwaka’s snare — details that were invisible in daylight step forward. The song itself stands on the night side of the day, if that makes sense.

Which lines up with how it came back around as the solo acoustic version for the beer ad. From April 2023 the track was used as the CM song for Kirin’s Tanrei Green Label, and from May of that year Hoshino appeared in the ad himself, performing it solo with a guitar. Full band or one voice and a guitar — a song that holds up in both shapes has strong bones in the chords and melody. Not many tracks stand up naked like that.

So try moving Fushigi out of your “drama themes” folder and into your “night listening” folder. I think the whole experience updates. When it actually clicks for you might be a different hour, a different room — honestly, that’s the fun part. Test it against your own week.

Two front doors: drama, then CM

The other thing worth flagging: this song has a two-stage tie-in. Round one, the 2021 drama theme. Round two, the 2023 beer commercial. In Japanese pop, a track getting a second promotional life two years after release isn’t especially common — and here they didn’t just re-use the recording, they re-tracked it as a solo acoustic performance.

The Kirin “Tanrei Green Label” TV commercial “GREEN JUKEBOX (Izakaya edition),” featuring Mikako Tabe, began airing nationally on May 9. That’s the moment the song stepped down into everyday life a second time. Since 2023, the crowd at his shows has included both people who first heard it as a drama theme and people who first heard it in that CM. That uneven arrival at the same song is what gives Fushigi its density on a re-listen now. One track, two front doors.

Chart-wise it was strong out of the gate too. On the Hot 100 published on May 5, Fushigi jumped straight up to number 2. I won’t dig deeper into the numbers than that. The foundation for a long life was clearly there from day one, and the CM placement two years on gave it a second push.

Where it sits in his catalogue: the twin to ‘Sozo’

You can’t really talk about Fushigi without talking about Sozo, the digital single that came right before it. Sozo was written as a Nintendo tie-in. Fushigi was written for a rom-com. Later they were packaged together as the physical single Fushigi / Sozo. Two songs aimed at completely different destinations — a game and a romantic drama — ending up in the same sleeve. That itself tells you something.

Play them back to back and the way mabanua is used, the way the synths are handled — the lines connect across the drama-vs-game gap. mabanua serving as co-arranger on Fushigi, following on from Sozo, is proof that during this stretch Hoshino was visibly raising the share of co-production in his work. Up through POP VIRUS in 2018, the dominant frame was “Hoshino Gen plus band.” From Fushigi onward, the frame that steps forward is “Hoshino Gen plus mabanua plus that circle of players.” This song sits right on the hinge.

Where to start listening now

If you’re new to the track, start with the original. That specific groove — Ishiwaka’s drums locking into mabanua’s programming — only really breathes in the album mix. Not on earbuds. Try a small speaker set a bit away from you, in a quiet room at night. Get those conditions right and the centre of gravity drops noticeably.

If you’ve already worn this one out, do the opposite: A/B the acoustic CM version against the original. Hearing the same song at two completely different densities is what makes the skeleton of it obvious. The rom-com “kyun” actually works with nothing but the bones. Once you can hear that, the song looks different.

Want to push past Fushigi? Start with its twin, Sozo — mabanua co-arranges there too, and it’s a different solution to the same puzzle of building humidity between live band and vintage synths. After that, go back to POP VIRUS. The collaborative logic in play there feeds directly into the lineup on Fushigi. With those two reference points in place, everything Hoshino has done since gets much easier to read.

Take the drama frame off, and look again

“Theme song for Kikazaru Koi ni wa Riyuu ga Atte” is the biggest door into this track. Fine. But there’s too much detail packed in here to consume it only through that label. Glance at the personnel — Ishiwaka, Hama Okamoto, Nagaoka, Sakurada, mabanua — and you can tell how much studio labour went into it. It wears a rom-com face and hides a mountain of studio craft behind it.

If you’ve been shelving Fushigi as “that cute crush song,” I think you’re leaving something on the table. Try it again — at night, somewhere quiet, letting the humidity of the synths carry the weight. Lines you couldn’t see in 2021 start showing up. Where you take it from there is up to you. Loving it as a rom-com theme is fine. Re-hearing it as the hinge in his catalogue is also fine. Honestly, once you can hold both readings at once, this song is at its richest.