Junjou Koushinkyoku (純情行進曲; Pure Heart March) is Nakazawa Yuko's third single. The single reached #29 on the weekly Oricon Oricon charts and charted for six weeks. It sold 10,630 copies in its first week and 26,820 copies over all. "Junjou Koushinkyoku" appears on the albums Petit Best ~Ki Ao Aka~, Dai Nishou ~Tsuyogari~, and Legend. The PV for "Junjou Koushinkyou" appears on Petit Best DVD, Nakazawa Yuko Single M Clips 1, andLegend.