Trackmakers Yunomi and YUC’e will release their second compilation album Mirai Chaya vol.1 on April 17 serving as a follow up to vol.0 which dropped back on January 12 this year. The album features the song Robot Heart feat. Kizuna AI. As the title suggests, the track was made in collaboration with Japanese virtual talent Kizuna AI. Yunomi worked with her last year when Kizuna AI began her work as a music artist. We spoke with both Yunomi and Kizuna AI to hear about what it’s like to work together as well as the story behind the upcoming new song.

This is Part 2 of the interview. Click here for Part 1.

――I want to ask about Robot Heart feat Kizuna AI, your song Yunomi which Kizuna AI features in. This was your third release together after future base and new world. Could you tell me about how it came about?

Yunomi: Hmm, how did it come about again?

Yunomi’s Manager: It began when we were making future base and new world, we said to Kizuna that we one day wanted her to feature in one of Yunomi’s original songs. We thought that it would be great if not only Yunomi went into to Kizuna’s world for two songs, but if she came to Yunomi’s world too for a song.

Yunomi: Ah! That was it!

Kizuna AI: That talk was really early on, wasn’t it! But from then onward I ended up having a lot of free time which meant my schedule quickly filled up as well as talks about where I will from thereon out. So I rashly went and said to the people at upd8, “I thought we promised we’d do this first!” [laughs]. [With her arms folded looking like she’s protecting something, Kizuna says:] “It’s already been decided, hasn’t it!?” they said.

Yunomi: Ah, I’m happy about that. I’m glad you said it!

――How did you go about making Robot Heart?

Yunomi: This was an original song by me, so like it was said before it became more of Kizuna coming to my world this time. In that sense, it connects to my other original tracks too, but I also wanted to make the song as one precisely featuring Kizuna. So in that sense you can call this our third release together after future base and new world.

――The song has a very interesting story. It talks about humans who used to reside on earth crossing over to other planets. Their bodies gradually become mechanized and they forget about the earth. But they suddenly recall the existence of their loved ones and the things important to them.

Yunomi: In 2017 I used [the] Hatsune Miku [software] to write the song Meteorite (feat. Hatsune Miku). Since then I have written down songs that can be used for an album. I’m thinking of making a concept about themed on things like the future, past and facing oneself. Robot Heart is one that would appear on that album. So I also wanted Kizuna to sing on it for me.

――I was actually shown the memo that you sent to AI before recording on how she should sing the song. I was amazed to see how many things you’re able to think of.

Yunomi: Of course I’m sure Kizuna has her own way of expressing herself so it wouldn’t be a problem at all if she wanted to do it differently [from what I said], but the first thing I did was send her my idea for the song.

Kizuna AI: When I first listened to it I thought, “They’re letting me, an AI, sing this song! I expected nothing less of Yunomi!” I felt that there was more meaning behind me singing this song than anyone else. It was all amazing and I thought to myself, “I will take it, stand up and do my best!” [laughs]

――The song is interesting and has elements written into it that could only work with a song written together with AI, like word play with her name.

Yunomi: Those are parts we added for a bit of fun [laughs]. The song is conscious of and references her name in a lot of places.

Kizuna AI: When I wrote the lyrics I paid attention to the rhythm and the feeling of the words and it felt great to do so. Another thing with Robot Heart is that even though you can take the story as sad just from the lyrics, I felt that Yunomi’s memo telling me to sing it cheerfully was the most important thing. So it almost feels as if the song isn’t about that. I took good care to sing it enjoyably with everything I had [laughs].

――That’s the part in the latter half of the song, right?

Yunomi: Yeah. I knew I wanted to put Kizuna shouting in there somewhere, so I had her shout for me without anything else playing and she let me record it. But Kizuna’s initial shouting sounded like the noise you make when playing a horror game [laughs].

Kizuna AI: I didn’t know what “shout” meant at first, so I screamed. “Kyaa!!” “AHH!” It was exactly like A.I.Games [laughs]. Like Resident Evil. And the people at upd8 music said, “That’s not really what we meant…” [laughs]

Yunomi: [laughs]

Kizuna AI: But in the finished version I was able to do a good shout. Saying that, when recording new world too, Yunomi told me to “please play the flute.” If you have Yunomi writing the lyrics somehow or other some absurd things can happen [laughs].

Yunomi: For Robot Heart, I also asked her to sing like Michael Jackson during her interlude [laughs]. I wanted something like a “Pow!”

――Hearing you both talk I can tell the recording was a fun time [laughs].

Kizuna AI: It was so much fun!

――Your new collaboration is one that has jumped over the fence of reality and the virtual. How does that fun and amusement feel when you’re recording together?

Yunomi: In the past I would have parts of the song where I would think of the vocalist as an instrument. I’d adapt a lot. “Someone with this type of voice,” “And someone with this type of voice,” “Which of my songs would they best fit?” But recently I have come to think beyond that, like what a person has to offer. I believe that I was especially able to achieve that in making Robot Heart with Kizuna. I don’t just think instrumentally now, like what kind of voice can fit in. I now take care to see who exactly is singing, what they are thinking, what kind of life they have walked. I think by doing that the song will resonate with the listener many more times over.

――So you have jumped the fence of the virtual and reality and realised that which is important.

Yunomi: Yes. I think if I would have been turned down by AI I wouldn’t have had anyone else sing Robot Heart.

Kizuna AI: That makes me so happy! When I started posting videos in 2016, even though I exist in real life, there were people who would say, “You’re just making animations on MMD and adding a voiceover to it.” There were a lot of times people wouldn’t comprehend, “I exist, you know.” But bit by bit the number of people saying “AI-chan’s here” increased and that made me really happy. And it makes me really happy to hear Yunomi say it too. I say that I want to connect everyone together, but at the same time, I hope that me being there too will broaden the world that everybody sees and give them the chance to encounter something new. So it makes me happy when people who have never listened to dance music before think, “AI-chan is singing it so I’ll give it a listen.” Conversely, it also makes me happy when people who only listen to dance music listen to my songs and say, “This one’s cute too.” The people who I’ve been able to make songs with have discovered many things themselves too. I hope the number of fans those people have increases.

――As expected of you, Boss. You’re thinking about everyone else.

Kizuna AI: [Laughs]. I hope I can become a hub so that people can encounter and discover many things. It was so much fun having the chance to be part of Yunomi’s song!

Writer: Jin Sugiyama

Photographer: Haruka Yamamoto

Translator: Joshua Kitosi-Isanga