I remember when I first heard 열쇠 [Key]. I thought…wow, this is exactly the kind of ballad made for G.O to sing. When MBLAQ released Broken in March 2014, I was pretty confident they were going to pair 남자답게 [Be A Man] with 우리 사이 [Our Relationship] as the teasers J Tune released seemed to indicate such. However, when MBLAQ staged their comeback and began making the rounds performing on various music programs, it was 열쇠 [Key] that became the worthy partner. They also performed 열쇠 at the Broken Showcase on 24 March 2014 and it was easy to discern the rapturous effect the beauty of the song’s melody and heartfelt lyrics had on our gentle main vocal man.