Everything began with a game manufacturer known as Elf. Elf is among the better game producers in Japan, and has produced some fairly good games in it's history. For the most part, none of these has anything to do with Kakyuusei, except the game known as Dokyuusei (Classmates), which is also often called Nanpa. Dokyuusei became a popular game not only because the artwork, but because of the good game play, and how the game worked. Dokyuusei was successful enough for Elf to release Dokyuusei 2. With these successes, Elf developed a third game which was much along similar in play, but had a completely different story line. Instead of calling the game Dokyuusei 3, it was decided to call the game Kakyuusei (Under-classmen). Kakyuusei is different in Dokyuusei in many aspects, mainly sporting even better artwork, and a longer period of time through which the game takes place. Kakyuusei was advertised as being only a "slightly H" game (which I always found funny). Kakyuusei does in fact seem to focus more on interacting with the girls, than H-ing with them, which is why Kakyuusei became known as the "younger sister" to Dokyuusei. Unfortunately many people quite often confuse Kakyuusei with Dokyuusei which is probably responsible for much of the perception that Kakyuusei is a hardcore hentai game.