In November 2015, Dario Marianelli was hired to score the film's music. The score had a cultural significance to
feudal Japan, and to incorporate it, Marianelli used ethnic Japanese instruments such as
shakuhachi,
taiko and
koto in addition to the
shamisen (a Japanese
stringed instrument, which is an integral part of the film's plot). Besides that, he also infused western and eastern music tendencies, with the use of contemporary instruments. Marianelli said, "What we know of our very crude perception of western music is the pentatonic scale that you find on the black keys of the piano [...] But in fact there is a wealth of variety of scales in the east, so just digging a little deeper and learning about Japanese scales brought into the music much more depth". The cues for Kubo, were delivered using
rock-and-roll and
soul music, to bring "an action film vibe" and "experimental, when played with a typical instrumentation". Marianelli opined that "It was a combination of very delicate, at times, and very soulful playing, but other times he can really unleash hell with his instrument and can be a proper rock and roller." The usage of contemporary and distinctive Western instrumentation and its blending with traditional Japanese, according to director
Travis Knight, was "a really beautiful combination of east and west in terms of the score and had these things melding together". He appreciated Marianelli's composition, further saying "the music that he did in this movie is the best thing that he has ever done. I think it’s absolutely exquisite. We’re feeling exactly what we need to be feeling, we’re hearing exactly what we’re feeling. And it really is an expression of understanding and emotion through music, I think it’s just a beautiful piece of work." Two music consultants from the United Kingdom and Japan were hired for the film, while
Kevin Kmetz from
Estradasphere, played the western and traditional Japanese cues through his Monsters of Shamisen band.
The Beatles' track "
While My Guitar Gently Weeps" (1968) was performed by
Regina Spektor which was included in the soundtrack. Speaking to an interview to
Entertainment Weekly, Spektor added that "The way Travis described to me his idea for the boys’ choir — the Asian instruments carry the song through, and then this orchestra sweeps in and then there's this boys’ choir that comes in at the very end. He said it's almost like the children taking on the song of the mother and being the ones to carry on the story, and I really loved that he saw it all."
Rolling Stone described the song as: "Marianelli’s arrangement weaves a dense tapestry of string instruments – including a solo performed on the shamisen, a three-stringed Japanese lute – before closing with a reflective piano coda." ==Track listing==