"Kuroi Shizuku" (Japanese: 黒い雫, "Black Droplet") is a song by Japanese musical act Superfly. Used as the theme song for the Fuji Television medical drama Mutsū: Mieru Me, it was released as a digital single on November 18, 2015, and as a physical single on December 2 as "Kuroi Shizuku" & Coupling Songs: 'Side B', a five-song extended play packaged with a B-side compilation album as a bonus disc.

In May 2015, the fifth original album by Superfly was released, White. Taking a year to write, the album was partially recorded in Los Angeles, when vocalist Shiho Ochi traveled there to collaborate with Chris Cester, the former lead singer of Australian Jet. Superfly worked together with American songwriters Jason Hill and Bonnie McKee, as well as Japanese singer-songwriter Bonnie Pink and the poet Bin Sugawara. The album was promoted primarily with the song "Beautiful", which Ochi wrote for the Mother Game: Kanojo-tachi no Kaikyū. Released digitally on May 8, the song was a commercial success, certified Platinum by the Recording Industry Association of Japan. From July 4 to December 14, Superfly performed a 39 date tour of Japan, entitled the White Tour. Part way through the tour, Superfly released McKee's contribution to the album, the ballad "On Your Side", as a post-album single.

The large single and bonus album package was created to commemorate this release being Superfly's 20th physical single release. This was the second time Superfly had released a package like this, after the drama theme song "Wildflower" and a compilation of Western cover songs, Cover Songs: Complete Best 'Track 3', were compiled together in 2010 to commemorate Superfly's 10th physical single.

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