単一指向性オーバーブルーム (Taniishisei Overbloom) is a crossover character song originating from SEGA's ONGEKI rhythm game, performed by Katsuragi Hana (CV: Wakana Maruoka), a member of the HaNaMiNa unit within the Maihara High School Light Music Club. The track was added to maimai DX during the Splash PLUS update on April 9, 2021, expanding the オンゲキ＆CHUNITHM (ONGEKI & CHUNITHM) crossover category. The title weaves together two motifs: 単一指向性 (taniishisei, "unidirectional," the term for a microphone's pickup pattern) and オーバーブルーム (overbloom, "over-flowering"). This wordplay evokes a solo vocal performance that bursts beyond its bounds, fitting for a character song centered on one performer's voice and presence. The song sits at 158 BPM with a lively pop-rock arrangement that suits Hana's bright, spirited personality within the ONGEKI storyline. Within maimai, this track holds a historical milestone: it was the first オンゲキ＆CHUNITHM category song to receive a Re:Master difficulty chart. The three highest DX charts were each handled by a different notes designer, ぴちネコ (Expert), Redarrow (Master), and はっぴー (Re:Master), giving each difficulty its own distinct character. The Re:Master chart at level 13+ (constant 13.8) challenges players with 1080 notes, including a notably high count of 93 Touch notes that demand rapid multi-touch coordination woven into dense Tap/Hold/Slide phrasing.