Nakajin, born Shinichi Nakashima on October 22, 1985, in Ōta, Tokyo, is a Japanese musician best known as the guitarist, leader, and multi-instrumentalist of the band SEKAI NO OWARI. In high school, his tastes shifted toward melodic punk, influenced by acts like Hi-STANDARD, leading him to play electric guitar. Joining SEKAI NO OWARI, Nakajin has been integral to the group’s sound since 2013, contributing as a composer, arranger, producer, and occasional lead vocalist on tracks like "TONIGHT" and "Goodbye". He plays a wide array of instruments, from guitar and bass to mandolin and shamisen, and often adapts his role to serve the song’s arrangement rather than prioritize guitar parts. Beyond music, he is a passionate ramen enthusiast and a licensed amateur radio operator. In 2024, Nakajin launched a solo career as a DJ and producer, debuting with his remix of Two Door Cinema Club’s "Sure Enough". In 2025, he co-wrote ILLIT’s hit "Almond Chocolate" with Pdogg, surpassing 50 million streams, and released his first solo single, "TOKYO", in July 2025.