[1][2][3] Choiza and Gaeko were friends since childhood and debuted in 1999 with the hip hop trio CB Mass.

It became the best-selling hip hop album in South Korea, with sales of 50,000 copies in the first month after its release.

[6] After establishing hip hop record label Amoeba Culture in 2006, Dynamic Duo released their third album, Enlightened, in 2007.

They released two more albums, 2008's Last Days and 2009's Band of Dynamic Brothers, before both Choiza and Gaeko began their mandatory military service on October 12, 2009.

Before being dispatched, both received basic military training at the same camp in Uijeongbu in Gyeonggi Province.