The 71st Emperor's Cup was held between December 14, 1991, and January 1, 1992. It was the last cup involving clubs from the old Japan Soccer League before it was reorganized into the J. League. The tournament was won by Nissan Motors, now known as Yokohama F. Marinos. The 12 JSL First Division clubs qualified automatically, while the other clubs qualified to the first round via regional qualifying cups.
References
1991 Emperor's Cup Wikipedia(Text) CC BY-SA