Originally developed by ELF Corporation in 1992, Dōkyūsei (lit. "Classmates") is widely considered a pioneer of the dating sim genre. It introduced mechanics that are now industry standards, such as a non-linear, time-management-based system where players navigate a town to interact with various heroines.

: Established the "nakige" (crying game) subgenre and influenced future giants like Jun Maeda.

The keyword refers to a modern adult OVA (Original Video Animation) series based on the 2021 remake of the foundational 1992 dating sim visual novel, Dōkyūsei . Produced by Pink Pineapple and directed by Takashi Nishikawa , the series serves as a high-fidelity adaptation of the "Reiwa-era" revival of the classic franchise. Evolution of a Classic: From 1992 to the Reiwa Remake