The 23rd Chess Olympiad (Spanish: La 23a Olimpíada de ajedrez), organized by FIDE and comprising an open[1] and a women's tournament, as well as several other events designed to promote the game of chess, took place between October 25 and November 12, 1978, in Buenos Aires, Argentina.
After the boycott two years earlier, the Eastern Bloc countries were back, including the Soviet team who, as usual, were huge favourites——but in the end they had to settle for the silver medal. Hungary, led by Lajos Portisch, caused quite an upset by taking the gold medals by a full point. The United States took the bronze.
This tournament also witnessed the debut of China, which placed 20th with six untitled players, and later became a chess power and won the Chess Olympiad in 2014 and 2018.
Sixty-five nations played a 14-round Swiss system tournament. To make for an even number of teams, the Argentine hosts also fielded a "B" team. In the event of a draw, the tie-break was decided first by using the Buchholz system, then by match points.
The following ratings were used to determine the placement (#).
Thirty-two nations took part in the women's Olympiad. From four preliminary groups the teams were split into four finals. In the event of a draw, the tie-break was decided first by match points, then by using the Sonneborn-Berger system.
The Soviet team was back, and led by newly crowned world champion Chiburdanidze they secured the gold medals in a superior display, as well as all four individual board prizes. On the reserve board, Akhmilovskaya won all of her ten games, the only perfect score in Olympiad history. Hungary and West Germany took silver and bronze, respectively.