The Dōkyūsei series(同級生, lit. Classmates) is a series of popular eroge by ELF. The original Dōkyūsei (also called Nanpa, meaning "pick-up", due to its batch file name "nanba.bat"), released in 1992 for the NEC PC-9801 microcomputer, is generally considered to be the first dating simulation. It was followed by three sequels: Dōkyūsei 2 (Nanpa 2) and Kakyūsei (下級生, meaning Lower classmates), both of which were also very successful. There was a four-episode OAV made from Dōkyūsei, a 12-episode OAV was made from Dōkyūsei 2, and both an OAV and TV series from Kakyūsei. In 2004, ELF released the next in the series of games, Kakyūsei 2.