- Hatsukoi Butterfly (初恋バタフライ; First Love Butterfly)
- Akimoto Yasushi
- Sugiyama Katsuhiko
- Other Information
- Arrangement: Ikuta Machine
- (Center: Tashima Meru)
- Team H: Anai Chihiro, Ueki Nao, Ota Aika, Kodama Haruka, Sashihara Rino, Shimono Yuki, Nakanishi Chiyori, Matsuoka Natsumi, Miyawaki Sakura, Murashige Anna, Motomura Aoi, Moriyasu Madoka, Wakatabe Haruka
- Kenkyuusei: Tashima Meru, Tomonaga Mio, Fuchigami Mai
There are currently two versions of "Hatsukoi Butterfly" to be found in HKT48's discography. These versions are:
- Hatsukoi Butterfly (Original)
- Found on the Type-C edition of the "Eien Pressure" single as track #3.
- Hatsukoi Butterfly off vocal ver.
- Found on the Type-C edition of the "Eien Pressure" single as track #6. This is the standard version without the main vocals.
- STUDIO48: "Hatsukoi Butterfly" lyrics