The world is all one !! is a pop song that originated from THE IDOLM@STER 2, the Xbox 360 and PlayStation 3 entry in Bandai Namco's flagship idol simulation series. Composed by Tomokazu Tashiro (田代智一) with lyrics by RIONA and arrangement by Keiroku Araki, the track was built around the game's guiding theme of "unity" (団結), the idea that a group of idols working together can overcome what none could face alone. Its chorus lyrics, which invite the listener to join hands with people across the world, directly embody this message. The song is performed by Namco Angel, a special cross-agency unit that brings together five popular idols: Miki Hoshii, Iori Minase, Yayoi Takatsuki, Hibiki Ganaha, and Azusa Miura. In maimai, the track was added with the GreeN PLUS update on February 26, 2014, and was initially classified under the COLLABO genre before being recategorized as GAME & VARIETY (ゲーム＆バラエティ) from PiNK onward. It remained playable until its removal from arcade rotation on December 15, 2016, and is no longer available on current cabinets. The maimai charts offer a glimpse into the series' early design evolution: the Basic difficulty originally debuted at level 1 during GreeN PLUS and ORANGE PLUS, and was later rebalanced to level 4 from PiNK onward, one of the early instances of a chart difficulty revision in the series. The Expert chart was also adjusted from level 7 to 7+ in the same update. The Master chart, designed by はっぴー (Happy), delivers a level 9 arrangement across 449 notes, while the in-game video is sourced from a performance recorded for THE IDOLM@STER ONE FOR ALL.