Meiyaku no Teigi (盟約の定義, tr. “Definition of a Pledge”) is a cancelled RPG that was in development around 1991 – 1992 by Human Entertainment, planned to be published for the PC Engine. While in an old magazine ad it was labeled as “science fantasy”, from the look of its characters and settings it looked more like a traditional medieval-fantasy RPG.
Some more details were published in the “Human Club Vol. 8” promotional leaflet, so if you can read Japanese and would like to translate a short list of its main features described in there, please leave a message below!