| "Key of Heart" / "Dotch" | ||||
|---|---|---|---|---|
 Japanese single cover | ||||
| Single by BoA | ||||
| from the album Made in Twenty (20) | ||||
| Released | August 9, 2006 (Japan) September 21, 2006 (South Korea) | |||
| Genre | ||||
| Length | 8:19 | |||
| Label | ||||
| Lyricist(s) | Gen Katō | |||
| Producer(s) | H-Wonder | |||
| BoA singles chronology | ||||
| ||||
| Alternative cover | ||||
 Korean single cover | ||||
| Music video | ||||
| "Key of Heart" (Japanese ver.) on YouTube | ||||
"Key of Heart / Dotch" is a double A-side single by South Korean recording artist BoA for her fifth Japanese studio album Made in Twenty (20) (2007). It was released in Japan as a CD+DVD on August 9, 2006, and served as her 20th Japanese single under Avex Trax. In South Korea, "Key of Heart" was released by SM Entertainment as her first digital Korean single on September 21, 2006. Compared to previous singles, the sales for "Key of Heart" were low in Japan, but this was due to BoA being preoccupied with other projects and the lack of promotion from Avex Trax.