SoulJa (ソルジャ, Soruja, birth name: Johannes Maria Leenders Zwaan) is a Japanese hip-hop musician and songwriter best known for his collaborations with singer Thelma Aoyama, "Koko ni Iru yo" and "Soba ni Iru ne" – the latter of which was the former Guinness World Records holder for the best selling digital single of all-time in Japan (until it was superseded by Greeeen's "Kiseki").
He has worked with various Japanese singers, including Thelma Aoyama, Issa, Rola, and Misslim.