knshow's capsule (TBD)

In Japanese, the word for 2D is "Ni-jigen." Since the "Niji" part is pronounced exactly like the word for rainbow ("Niji"), there is an internet slang in Japan where "rainbow" is used as a metaphor for the 2D world—specifically when it centers around cute girls.

I also suspect this slang was born because otaku culture was often looked down upon back then.

This is just my guess since I don't know the exact details of its origin, but it feels like the term isn't used much these days.

I suspect the title "RAINBOW GIRL" was inspired by this—essentially meaning "A Girl from the (2D) Rainbow World."

While this is just my own theory, I believe it hits the mark.

[Vocal Range]

B2 - G#4 (mid1B - mid2G#)

[http://...fc2.com]Source: Vocal Range Database

[Karaoke Availability]

It will likely remain unavailable. I'll explain why in the "My Thoughts" section below.

[My Thoughts]

If you're Japanese and love internet culture (2ch, niconico, VTubers, etc.), you've likely heard this song at least once.

2007年3月にニュー速VIPの作曲スレで生まれた「RAINBOW GIRL」。

あの楽曲は「みんなでワイワイ遊ぼうぜ！」という空気ででっかく育ちました。

To translated:

"RAINBOW GIRL" was born in March 2007 within a composition thread on 2ch's "Breaking News (VIP)" board.

As Korosuke, the person who started the thread, put it: "This song grew so large because of the atmosphere of everyone just having fun together!"

The song originated from the thread "Hey, composers, get in here!" on 2ch (now 5ch).

First, the lyrics were posted (Thread 41, Post 673), and then the music and vocals were created in response (Thread 43, Post 437).

March 2007 was just before the birth of Hatsune Miku (who debuted on August 31, 2007).

Back then, people used the slang "Ore no Yome" (My Wife) to refer to their favorite 2D characters—what we now call "Oshi" (one's favorite or "stan").

This song was written from that "My Wife" perspective.

Whether it was an anime character, an eroge character, or Hatsune Miku, everyone listened while projecting their own feelings. I believe that's why it remains so popular.

Specifically, I feel the fragile yet powerful vocals by Isaka Tonasa (the composer/original singer) captured many people's hearts.

It was only because "everyone was there" that it continues to be listened to and covered today.

Naturally, many fans hoped for a karaoke release.

However, due to its origins (anonymous lyrics and music on a message board), it remained unfulfilled for years.

While researching for this article, I found that the lyricist has personally come forward to clarify their stance on the site:

※以下は作詞者・コロ助個人の方針です。

作曲者・いさかとなささんの意向ではありません。

あらかじめご了承ください。

1. クレジットは“生まれ順”で

「RAINBOW GIRL」は詞が先、曲が後。そこで、表記は次の並びでお願いします。

作詞：コロ助（41スレ673）

作曲：いさかとなさ（43スレ437）

2ちゃんねるニュー速VIP「作曲できる奴ちょっとこい」スレ

2. 基本 OK なこと

●YouTube などへ無料公開のカバー動画（広告付きも可）

●ライブやイベントでの演奏（チケット代・投げ銭・スパチャ OK）

●期限付きの有料配信チケットでの視聴

要するに「その場を一緒に楽しむ」範囲なら遠慮なくどうぞ。

3. ただし恒常的な“商品化”はご遠慮を

あの楽曲は「みんなでワイワイ遊ぼうぜ！」という空気ででっかく育ちました。

なので、、、

●CD・DVD・ダウンロード販売など、形に残して売る

●Spotify や Apple Music など、サブスクで常時流通させる

●ゲームや映像作品に楽曲を組み込み、永続的に有料配信する

こういった「がっつり商品」にする場合は、いったん立ち止まってください。

お金儲けそのものが悪いわけじゃないのですが、当時のスレの雰囲気を尊重したいのです。

[Web]Source: 作曲できる奴ちょっとこい　ｂｙコロ助

To translated:

Note: These policies belong to the lyricist, Korosuke, and do not necessarily reflect the views of the composer, Isaka Tonasa.

1. Credit by Order of Creation

Since the lyrics came first, please credit as follows:

Lyrics: Korosuke (Thread 41, Post 673)

Music: Isaka Tonasa (Thread 43, Post 437)

From: 2channel "Breaking News (VIP)" Board "Hey, composers, get in here!" Thread

2. Generally OK

●Cover videos on YouTube (including monetized ones)

●Performances at live shows or events (tickets, tips, and Super Chats are OK)

●Limited-time paid streaming tickets

In short: Feel free to use it as long as it's about "enjoying the moment together."

3. Please Refrain from Permanent Commercialization

This song grew large because of the "everyone playing together" vibe. Therefore, please stop and think before:

●Selling physical copies (CD/DVD) or digital downloads

●Distributing on subscription services like Spotify or Apple Music

●Permanent paid distribution via games or video works

"It's not that making money is bad, but I want to respect the atmosphere of the original thread."

"I want to respect the atmosphere of the original thread"—niconico was exactly like this in the beginning.

Vocaloid producers would provide off-vocal tracks, and everyone would cover them. That was the vibe.

Eventually, individual interests took priority over that atmosphere, and many moved to YouTube.

Considering this history, I believe the song will likely remain unavailable for karaoke—and honestly, I hope it stays that way.

(Though it's a bit of a shame we can't sing it at karaoke!)

So, while it’s not a Vocaloid song, I wanted to introduce it.

Wouldn't it be interesting if music started originating from Geminispace someday?

==================================

Last updated:

2026-05-03 00:19 JST (Japan)

2026-05-02 15:19 UTC (Universal)

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