Dōkyūsei (同級生, lit.
"Classmates") is an adult-themed dating sim series created by ELF Corporation.
The original Dōkyūsei, originally released in 1992 for the NEC PC-9801 microcomputer, is generally considered to be the forerunner of the modern dating sim.
It was followed by sequels: Dōkyūsei 2 and Kakyūsei (下級生, lit.
There were multiple OVAs made from Dōkyūsei, a 12-episode OVA series (and three extra) from Dōkyūsei 2, and both OVAs and TV series from Kakyūsei and Kakyūsei 2.