an Entity references as follows:
"So Long!" (stylized as "So long !" with a space before the exclamation mark) is the 30th major single by the Japanese idol girl group AKB48. It is also AKB48's sixth cherry blossom-themed single, and its first single of 2013. This single was released in Japan on February 20 in four different versions. The 64-minute-long music video for the title track is directed by director Nobuhiko Obayashi. The Nippon Television network aired a 3-episode special television drama based on the title track from 11–13 February 2013. This is also the last single to feature long-time member Tomomi Kasai.