"Koi no Tsubomi" (Japanese: 恋のつぼみ) is a song recorded by Japanese singer Koda Kumi, serving as her 31st solo under Rhythm Zone. 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 number two on Oricon, selling over 140,000 copies in its first week and staying on the charts for 21 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.