"Love Letter" is a song by South Korean singer BoA, serving as her 23rd Japanese single.

[2] It was directed by Kensuke Kawamura, who also served as the director for her single "Make a Secret" in addition to videos for other artists including Namie Amuro, Kumi Koda and Mika Nakashima.

"Beautiful Flowers" was chosen as the theme song for Japan's Central League baseball team Yokohama BayStars.

"Diamond Heart" was promoted during the summer of 2007 on commercials for the Toshiba W53T, featuring BoA herself.

On May 9, 2022, a re-recorded version of "Love Letter" with new acoustic instrumentations was released for her 20th anniversary compilation album The Greatest (2022).