This is one weird way to do it then with an unfinished demo. I would like this to have been planned but it seems so unlikely.

It's very unlikely to be a mistake. It has a cover (a very simple one) and as far as I know, Spotify requires a cover to release a song and it is produced by artist's management. Sounds like they are trying to get free media exposition by mystery. Don't know if it's working, but it's definitely intriguing.

It does look intentionally, but why doing it with an instrumental and not a full song?
The impact would be much bigger with a full song, when it works. Like that it's just strange.

It does go in the same direction as Words.
Don't fancy, hope we'll get some variety with the album.

They sent the demo to several streaming plataforms.
The demo has a cover, as it was already pointed.
It wasn't taken off, something far easier than publishing it.
Them you have a playlist created by her team, with the songs clearly having a though out order.
The demo appears in the playlist, right after her biggest hit.

Ern...

Maybe they are testing the impact of the song with audience. "If people get interested, let's work with that, if not, we can considerate others".

Whatever this is, I don't really think it was a good way to go about it. I love when artists do teases but this doesn't feel at all intentional.

Didn't she release the Rainbow instrumental before the actual song as part of the promotion for RAINBOW/A Ballads?

Hm, but the thing even misses a proper title.
So how should any more casual listener recognize the full song with vocals and mixing later on?
Like that it's likely people will listen to it, noticing vocals and title and all are missing and not thinking about it any further, categorizing it as mistake like people here do as well.
A title would at least suggest there's a thought behind it, a strategy maybe.

^This isn't the kind of promotion you use to attract casual listeners.

On the same way a casual listener couldn't care less about having TA Members singing back up vocals for a song or about a mystery snippet of a unhead song on one of her albums.

That was more of a campaign. First press of Rainbow came with a code you could enter into a website to download a short instrumental clip of the song, and then you could submit words/lyrics/thoughts that it inspired in you - she read them all and used them to inform the lyrics of Rainbow when she later wrote them. Then the song was released on A Ballads after the completion of the campaign.

^If she actually read all of them, them there most likely weren't that much of them. In other words, this wasn't something casual listeners were excited about.

This kind of promotional tatics work for those already converted, on the same way not releasing stuff for a longer time only impact those who already had a chance of buying her stuff.

IMO she is simply working with the fact that her fanbase is anxious for a new release by leading them into getting curious about this demo that magically appeared on her streaming profiles and summer playlist.

Considering the whole description of the playlist is in Japanese, this is not something done with her overseas fandom in mind and if her japanese fans speculating about it on social media bring attention for whatever new release she is clearly planing, the campaign worked.

It's not like she started this whole thing with the demo. She didn't release anything for longer than her usual, kept on hinting on social media that something will be released soon, is sharing videos from her record sessions with the public, etc. I remember someone saying on her social media thread that they would go into the studio way more confortable than she was if they were there to record music. She most likely does, when there isn't plans to film or photograph it for promotional purposes (and when she isn't being paid to wear ugly ass shoes to promote them :B)

The whole thing is pretty much a promotional effort aimed for the japanese public that follows her through social media and digital music plattaforms.

A few fans posted screenshots on Twitter that showed she produced this. This is obviously her just giving us a glimpse of what she's working on (and perhaps wants fan input like the RAINBOW lyrics / You&Me remixes), but maybe CREA is making an appearing on the new album?

Where are these prints? I'm curious about that. Was it on metadata file?

Yeah, it's just 'Toru Watanabe & ayumi hamasaki' in the composer section. But may just be her lyricist credit squished in.

I wish I could tell you how to find that info on Spotify, I just saw screenshots online.

OMG WAS NOT EXPECTING THAT?!?!

I have the feels for itttt

Oh, I just saw that. Judging by the way it's listed in other songs, it's just the lyricist credits.

Is this a new composer?

He is for Ayu, he has worked for Koda Kumi (you) or AAA (Lights) and for a bunch of idol groups

If I'm not mistaken, he composed Koda Kumi's "you".

EDIT: found this link listing some of his works.