Toshiaki Monma (門馬敏明, Monma Toshiaki) is a bass guitarist best known in the VOCALOID community for performing as part of MKP39, the band that performed in the 2011 Tokyo and Sapporo VOCALOID concerts (Hatsune Miku Live Party Mikupa) and, subsequently, at the 2011 Singapore VOCALOID concert as part of Rock Your Soul - Super Anisong Concert. He and the rest of the band returned to perform in the 2012 March 8 VOCALOID concert.