I'm not that well-versed with his works, such as Haisuinonasa or the other media he has worked on, but I think I can say that I'm a huge fan of his works on both Jujutsu Kaisen and siraph.
Jujutsu Kaisen has been a great series to me, as a previously hardcore weeb, now kind of retired i guess. Sure, it doesn't have a really deep or complex story, but I like those two, and I can say that I love both the animation direction and, specially, the Soundtrack used for the franchise.
The first season and movie OSTs contain works from three distinct composers, and I really like that aspect of the show. You can tell that this period was a experiment of sorts, to check in which direction should it go. Not only on animation, designs or focus, but also on music and sound design. But I'm going to try my best to describe each of the artists' purposes here:
First, Hiroaki Tsutsumi, a renowned composer responsible for lots of different animes, including Dr. Stone, which Soundtrack I also adore. On top of my head, the things he provided in these scores were a deep connection with the traditional and almost ritualistic nature of the Jujutsu Sorcery, reflected by the use of deep percussions, female voices and classical instruments, combined with solemn sounds and strong electric guitars or synths in the more energetic parts of the tracks.
One of the more influential songs he made was 腹の底から出た本音 (The Words That Came From Deep Inside My Gut), used in some crazy scenes according to a deleted user on Reddit, those being Itadori's "last words" to Megumi, and Junpei's death by the hands of Mahito omg what a sick scene <- Spoilers. Also he was the composer responsible of REMEMBER, so he may be much more important than one might think for the series.
Next, let's talk about Alisa Okehazama. She's a relatively new composer, starting on 2020 with The God of High School and Jujutsu, later working on The Apothecary Diaries along with Satoru Kosaki, another incredible composer.
She's more focused in an EDM-focused work, applying atmospheric and otherwordly sound design, although she isn't afraid of using more acoustic instruments in order to create something interesting and tenseful.
A great song that perfectly encapsulates my description is 7:3, Kento Nanami's main theme, which provides a cool way to represent his demeanor. He may appear as a serious, hardworking and strict sorcerer, but he's extremely emotional and takes great responsibility on the safety of his colleagues and apprentices.
Then there's Yoshimasa. In comparison, he worked on the fewest amount of tracks in the first season, but he added something that remained for the rest of the series.
And that is the power of math! (Rock)
Take this track for example, Attack of Cursed Corpse. Although it's on 4/4, the track feels at first nonsensical and all over the place. However, as it progresses, more and more instruments starts appearing and create some sort of polyrhythm that combines the track to a really cool piece about, for example, an explanation or a training montage, for our protagonist, who's known for being erratic and unorthodox in his techniques.
Then, a great example of the way Yoshimasa creates unique combinations, Working Overtime. At first, the countermelodies go hand-on-hand, combining spliced voices with piano, bass and drums. However, next there's an amazing break that features a guitar riff, common of his style, along with a piano playing some weird chords, almost like getting in the zone. That works perfectly for the two scenes it appears, both featuring Nanami and Itadori, mentor and trainee, connected by their innate talent with Black Flashes. Coincidentally, this theme's remixed on We Are Stop the Attack, used on JJK 0, and it's a pleasure to listen to.
And the way I think of it is that Yoshimasa worked a lot with the other two composers, and used their unique aspects to create an extremely cool result, adding his jazziness and weird metrics and stuff to the mix. And that aftermath was what finally led to the identity of the OST, and with him working as the main composer for the remaining seasons.
And that coolness is upped to an 11 with the next season. And I think the best example is with Satoru Gojo's theme, Limitless Cursed Technique. The grandness and intensity of it perfectly encapsulates the sheer difference that he has with the rest of society.
With this and other tracks of the series, I can conclude that Gojo's songs distinct from the others on the BGM with the usage of a grand piano, along with extremely unique chords and melodies that makes you think "This guy's a genius". Untouchable, powerful, the strongest.
I also love when he references melodies from the previous season. One of these renditions is the one at Boogie Woogie and What Was Entrusted to Me, which really cleverly uses claps, Todo's cursed technique, as part of the track, further deepening the brotherhood of them both <- mild spoilers and characterizations.
Finally, the third season provides a different but equally incredible approach for its musicalization. With the emotional turmoil that Itadori has due to the massacre of Sukuna in Shibuya, and the overall darker tone that the film gets <- description of the context. This is heavily demostrated with Brothers Are Just Like That, a heavily reverbered piano along with soft strings, that showcases the way Choso shares the guilt of his little brother, Yuuji <- significance of the track.
I'm just excited with what Yoshimasa has prepared for the rest of the season and series. And if he doesn't get the chance, I just hope that the next one can grab the atmosphere needed for the rest of the story and make it their own.
Next up, I'm going to give a list of cool tracks from the series that I think deserve recognition:
siraph's a band that started on 2016, which includes Yoshimasa as the guitarist and one of their composers. It also has Annabel as the vocalist, a really cool artist with some incredible projects.
(Other members: Hideaki Yamasaki as bassist, Satoshi Yamashita as drummer, Masayuki Hasuo as keyboardist, mastered by Masayo Takise, mixed by Atsumasa Terui, Yoshimasa's brother (just found out lmao), and recorded by Yuya Tokunaga)
In here you can really get to know the inspiration and process of his work. Since in here he doesn't need to match a media's needs, he really gets to shine his Math Rock-esque arrangements and structures. Adding Annabel's voice, it creates a rich, almost ethereal ambience. It's that good, really.
I can't recommend the band enough. I recently listened to their entire discography on Spotify and it has lots of cool things to explore.
I personally want to highlight Jikan wa Tsugu. It has lots of movement and the sound design is amazing. The way the beat's constantly's being marked makes it feel like a march, which is a neat feature.
So yeah, stream Yoshimasa and siraph if you liked the way I praised them, please and thank you.