"The Power of Smile/Remember the Kiss" is Kokia's 10th single, released on September 24, 2003. It is currently Kokia's most commercially successful single, after being used as the Kao Essential Damage Care shampoo commercials in 2003, featuring actress Yūko Takeuchi.

This single was the second of Kokia's to be released under Victor Entertainment management, after being managed under Gai Records for her second album Trip Trip and Pony Canyon for her debut Songbird. "The Power of Smile/Remember the Kiss" was Kokia's first single released after her long-charting hit "Kawaranai Koto (Since 1976)," which had been used as the daytime TV drama 's theme song. Despite the song barely breaking the top 50 Oricon chart, it managed to sell 26,000 copies. And is listed as gold on the RIAJ Japanese chart database

Other than through Kao commercials featuring "The Power of Smile," the single was promoted in a variety of ways. Kokia was featured in September issues of magazines CD Data, CD-Hits, Weekly Oricon and What's In?, and appeared on a multitude of radio shows at the time. Kokia appeared on popular TV show Music Station to perform the song on October 17, more than three weeks after the single's release. This was the first time that she had appeared on the program.

The music video for "Remember the Kiss" was played after episodes of TV show Saku Saku throughout December 2003, and featured often in the music video shows Hot Wave and V-Clips.

"The Power of Smile" is an upbeat pop song, backed with piano, guitar and percussion. It begins with an introduction featuring only piano, guitar and Kokia's voice. This leads into verses and choruses arranged with percussion, with heavier layering of percussion around the choruses. The initial sparsely arranged section repeats itself for a short instrumental section in the song, as well as in the song's refrain. The song ends with a heavily struck piano note and Kokia's voice fading away, along with faint giggling songs from Kokia. The lyrics describe somebody walking along, humming to themselves to the music of a portable music player. The protagonist of the song expresses their happiness, and how they want to give someone they like "a smile that boils up into them." They then describe how powerful a smile is, and how it "projects a way of life" and how contagious smiles are.

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Wikipedia