Kokoro to Iu Na no Fukakai — Exploring Ado’s Most Emotionally Complex Song

A lyrical deep dive into Ado’s portrayal of emotion, perfectionism, and the loneliness of modern life.

Why do I write these? Because I love thinking about lyrics. So from time to time, I’ll use this newsletter to do exactly that. Let’s start with one of the most haunting songs Ado has ever released:

Song: “Kokoro to Iu Na no Fukakai”

(“The Mystery Called Heart”)

This song explores a deep emotional struggle—trying to control your feelings with logic, only to fall into a cycle of self-hate and confusion. It uses medical words to describe emotions, treating them like illnesses written down in a patient’s file. But that approach only makes things worse—because real emotions can’t be fully explained or diagnosed.

At the beginning, the protagonist says they can hear even the smallest sounds—like someone blinking or looking away. This shows how sensitive they are to others, but sadly, not to themselves. Even with this sharp awareness, they say they don’t expect anything from their own “kokoro” (heart), showing how little they trust their own feelings.

Later in the lyrics, the protagonist tries to analyze their emotions like a machine, using words like “no error” and “perfectly recorded zigzag.” They want to control their heart with logic, but at the same time, they say things like “I don’t believe what’s not written in my medical record.” This shows a fear of emotions and a need to distance themselves from their own feelings.

A key phrase in the song is:

“Shin’on wo haite iru”

(心音吐いている / “Breathing out heartbeats”)

Even though heartbeats mean you’re alive, the protagonist describes them like system errors—like they’re just signs of a body working without emotions. For them, emotions feel like bugs in a program.

The question, “How should I judge my emotions?” is at the center of the song. The protagonist wants clear answers, but emotions don’t work that way. This leads to painful lines like:

“Hyōjō ni mesu wo ireru”

(表情にメスを入れる / “Cutting into facial expressions”)

“Aijō wo tōyaku to omoeru”

(愛情を投薬と思える / “Treating love like medicine”)

They try to handle feelings as if they were medical problems, which only pushes them further away from true emotions.

At one point, they admit:

“Ranbō ni kimi ga furete kuretara”

(乱暴に君が触れてくれたら / “If you could touch me roughly”)

This shows they actually want emotional connection, but they don’t know how to reach for it. They can’t even understand their own emotions without turning them into symptoms.

The last line is:

“Kono omoi no namae wa nan na no?”

(この想いの名前は何なの？ / “What is the name of this feeling?”)

It’s a question without an answer. Naming the feeling might help—but the song never finds that name. Instead, it shows how our need to label, control, and understand everything logically can lead to deep loneliness and pain.

This song also reflects a problem in modern society: we value clarity and efficiency so much that we try to get rid of anything unclear—even in our hearts. But emotions are meant to be messy. By trying to clean them up or explain them like a science problem, we sometimes erase the very things that make us human.

In the end, this is a song about modern loneliness—the kind that comes from trying to be perfect, from fearing our own feelings, and from not knowing how to truly connect with others. Through dark humor, sharp self-criticism, and powerful imagery, Ado gives voice to a quiet kind of pain many people feel—but rarely talk about.

Thanks for reading. If this kind of deep dive is your thing, I’ll be doing more of these in the future. Subscribe for free and stay tuned.