Credited as SPIN (also as UNITe in some works), they are a unit of two Japanese lyricists, musicians and producers 井上純 (Jun Inoue) and 北川吟 (Gin Kitagawa).
SPIN / UNITe has provided lyrics for many famous Japanese artists, including 嵐 (ARASHI), KAT-TUN, and 氷室京介 (Kyosuke Himuro). Evoke Music Japan Vlog has featured a total coverage interview with SPIN on their YouTube Channel in 2023. (source provided by @mayuta)
