"Key of Heart" is BoA's 20th Japanese single and 6th Korean single. The single was available solely in CD+DVD format in Japan with a "special summer low price" and first pressing to commemorate this for being her 20th single.Compared to previous singles, the sales for "Key of Heart" were low, but this was due to BoA being preoccupied with other projects and the lack of promotion from Avex Trax.
"Winter Love" is BoA's 21st Japanese single. It was released on November 1st, 2006. It hit #2 on the Oricon Charts with sales of 42,481, making it the highest charting BoA single since "Do the Motion", which was released in March 2005. Formats are ?CD+DVD? and ?CD only?.The single was released just before her twentieth birthday (November 5, 2006).This single has met with success compared to her last single "Key of Heart / Dotch", and has outsold "Nanairo no Ashita: Brand New Beat / Your Color".
"Sweet Impact" is BoA's 22nd Japanese single. It was released on April 25, 2007 and it hit #5 on the Oricon chart on its first day of release. The song "Sweet Impact" was first featured in Japan's FASIO commercial in January 2007. The video was inspired by Michael Jackson's Moonwalker The single has approximately sold over 5,000 copies in Korea. It is also her first single to feature different cover art for both the CD-Only and CD+DVD versions.
