Kousui, written as perfume in Japanese, is a song by Japanese singer Eito that was first released in 2019 and spread widely online in 2020 through short video covers and social media shares. Its chorus became familiar far beyond its original release as amateur singers recorded their own versions. The phrase in this title means singing Perfume, reflecting that cover culture. Short excerpts like this one keep circulating in edits and soundboards because the melody is instantly recognisable and easy to reuse.