"Koi no Tsubomi" (恋のつぼみ / Bud of Love) is Koda Kumi's 31st solo under the Rhythm Zone label. It was the first single to bring in the new era after BEST ~second session~. The single was released in CD and CD+DVD and charted at #2 on Oricon, selling over 140,000 copies in its first week and staying on the charts for twenty-one weeks. It became the highest selling song debut for a female artist, until Ayumi Hamasaki surpassed it with her single Blue Bird, which came out a month later on June 21.