The Yakyuu Ken Special: Konya wa 12-kaisen (THE野球拳スペシャル ～今夜は１２回戦～) is originally a 1994 pornographic 3DO game made by Societa Daikanyama called The Yakyuu Ken Special: Konya wa 8-kaisen (THE野球拳スペシャル ～今夜は8回戦～). The same company made a Sega Saturn adaptation in 1995 and both versions were released exclusively in Japan. Despite what the name says, it is not a baseball game — it is a rather simplistic pornographic game where the goal is to get some young, dancing women to strip for you by beating them at rock paper scissors. This version features 4 exclusive women.
It doesn't have a Sega rating; a small warning saying the game is only for adults is placed at the top right corner of the front cover (Sega of Japan's master list gives it an X).