Kinuko Hiramatsu prefers to create shadows in her music. Her work as Sapphire Slows alludes to the idea that in a hyper-intense city like Tokyo there are still pockets with little neighborhoods that take things far slower. Her music isn't meant to dominate. Even her lead vocals are kept lower in the mix, drenched in reverb, to retain a sense of sound being overheard. The 10 tracks collected for her debut album on the Los Angeles–based Not Not Fun label are subtle, low-key tracks meant to be slipped into the sets of DJs who excel in not drawing attention to the artists but prefer an anonymous mix of danceable rhythms that evoke a solemn, reflective tone. Among the repetitive synth hooks on “Fade Out,” one hears Hiramatsu singing something elusive that can’t be fully transcribed. There's an even further attempt at anonymity on the sparse bass-and-synth “Third Party,” which nearly exposed by the austere arrangement. By insisting that her vocals be just another instrument in the mix, Hiramatsu sacrifices a quicker route to fame. Who's the woman behind the curtain, buried in the textures? Maybe we aren’t meant to know.