Coin Jackson,�Korea's first�'hip hop a capella' girl group,�made their first public appearance at December's "Blinding December" concert. Held on December 29th, the girls performed their title track, "Feedback", and earned an explosive response from audience members for their powerful music and dance. Shortly after the concert ended, they got together with December backstage for a friendly photo. Coin Jackson is currently the #1 most sought-after group to guest at year-end concerts, and previously headlined for performing as sexy Santas during a professional basketball game on the 24th. December stated, "I'm thankful that such talented juniors came to guest at our concert. We hope that people will give us their attention for our remaining two concerts." Source: Newsen via Nate