Sasaki Saku just dropped a cover of 39, the sasakure.UK x DECO*27 track featuring Hatsune Miku, and the timing says everything before the first verse even starts. This is one of the most quietly meaningful songs in the Vocaloid catalog, and Sasaki Saku picked it up and made it hers.

What “39” Means and Why Sasaki Saku Chose It

If you know Vocaloid culture, you already know the number. 39 is shorthand for Miku herself, and read aloud in Japanese it also lands as “san-kyuu” — a wink at the English “thank you.” sasakure.UK and DECO*27 built the original around that pun back in 2012, releasing it to mark Hatsune Miku’s fifth birthday as a message of gratitude to every listener, creator, and fan who kept her voice alive. It’s not a love song. It’s a thank-you letter set to music.

That context makes Sasaki Saku’s choice feel deliberate rather than random. Her video description is just one line — a simple “thank you to everyone” — and it’s hard not to read that as her borrowing the song’s original spirit and pointing it straight at her own fanbase, the Sasakids, rather than treating it as just another cover pick.

The Sound of Sasaki Saku’s “39” Cover

The original track leans on a rock-tinged arrangement dense with guitar work from DECO*27 and yuxuki waga, and that energy is still the backbone here. What changes is the delivery. Where Miku’s vocal is synthetic and precise by nature, Sasaki Saku‘s take brings a warmer, more conversational read to the same melody — the kind of performance that makes long-time listeners hear lines they’d stopped noticing after a decade of the original circulating. She doesn’t try to out-sing the source material’s technical cleanliness; she leans into the parts a human voice can do that a Vocaloid can’t, letting small cracks and breaths carry weight in the quieter passages.

Visuals and Production Credits

The illustration work comes from two artists, 春夏 and 苫苫苫, giving the cover its own visual identity rather than leaning on the original’s artwork. なつめ千秋 handled the mix, and the movie/video work is credited to SHIG. It’s a tightly assembled cover package — nothing overproduced, just a clean frame for the vocal to sit in.

Sasaki Saku’s History With Music

This isn’t a detour for her. Sasaki Saku has performed at Nijisanji concert events over the years, including group performances alongside other Nijisanji talents, and covers like this one are where her music side gets to breathe outside the structure of a full concert production. Picking a song this loaded with meaning — a thank-you song, from an artist whose entire relationship with her audience runs on gratitude and Kansai warmth — tracks with how she’s approached music before: personal, not just promotional.

Why This Cover Lands

“39” has been covered more times than almost any song in the Vocaloid songbook, which makes it a hard one to make feel fresh. Sasaki Saku‘s version doesn’t try to reinvent the arrangement — it doesn’t need to. What it does is redirect the song’s original purpose back at her own community, thirteen years after Miku first sang it to the world. That’s the whole appeal here: familiar song, sincere reason for picking it.

Track Credits

• Title: 39
• Original Artists: sasakure.UK x DECO*27 feat. Hatsune Miku (初音ミク)
• Vocals (Cover): Sasaki Saku (笹木咲)
• Illustration: 春夏, 苫苫苫
• Mix: なつめ千秋 (Natsume Chiaki)
• Movie: SHIG
• Label: NIJISANJI (ANYCOLOR)
• Released: August 12, 2026

▶ Watch: Sasaki Saku — 39 (Cover) on YouTube