Román Hernández Onna was a Cuban chess Grandmaster and twice national champion. Born in December 1949, Onna became an International Master in 1975 and achieved the title of Grandmaster in 1978. He won his first Cuban Chess Championship in 1971 and the second one in 1973.
Onna participated in a total of seven Chess Olympiads between 1970 and 1986. He also took part in the 1971, 1974 and 1977 versions of the World Chess Championship Interzonal tournament.
During his career, Onna had notable victories over many world-class players like Eugenio Torre, Walter Browne, and Zoltan Ribli.
Onna passed away in March 1998.