Gaon Albums Chart
Their first album as a duo, "Keep Your Head Down" was released in January 2011. U-Know Yunho and Max Changmin recorded the album between 2009 and 2010, and had to re-record some tracks after their split. "Keep Your Head Down" was a commercial success upon its release, peaking at number one on the "Gaon Albums Chart" and maintained that position for two weeks. "Keep Your Head Down" received generally positive reviews from music critics and had nearly 240,000 shipments by mid-year, winning Gaon's Album of the Year award for the first quarter of 2011.