OVA series: The Nationals Arc Doubles 2 of the finals: Inui-Kaidoh pair vs Yanagi-Kirihara pair. Inui's best data and Kaidoh's Tornado Snake are ineffective against Rikkaidai's pair. Inui seems ready to give up, but Kaidoh uses Yagyuu's Laser Beam. Kirihara transforms into a demon, purposely aiming at Inui and injuring him severely. Kaidoh turns into a demon himself, but was stopped by Inui. Soon after that, Inui collapses, Seigaku forfeits the match, and Inui is rushed to the hospital. This is the episode when they also find out that Ryoma lost his memory while he was still back in Karuizawa with his father, Echizen Nanjiroh. But while they were training for the National Finals something happened to cause Ryoma to lose all his memory about tennis. (thetvdb.com)