"A Bikini Divides the Eyeline Between Top and Bottom, but a One-Piece Shows Off the Figure so They Only Flatter the Slender" (ビキニは目線が上下に分かれますけどワンピースは身体のラインが出ますから細い方しか似合わないんですよ Bikini wa Mesen ga Jōge ni Wakaremasu kedo Wanpīsu wa Karada no Rain ga Demasu kara Hosoi Kata Shika Niawanain desu yo?) is the thirteenth episode of the Toaru Kagaku no Railgun anime series. It was first broadcast on December 25, 2009.