An attempt was made in 1924 to include chess in the Olympic Games. However, because it was very difficult to distinguish between amateur and professional chess players, the event was called off. While the 1924 Summer Olympics was taking place in Paris, the 1st unofficial Chess Olympiad took place separately from the Olympics, but also in Paris. The Fédération Internationale des Échecs (FIDE) was formed on the closing day of the first unofficial Chess Olympiad. FIDE organized the first official Chess Olympiad in 1927 in which there were 16 participating countries. By the 29th Chess Olympiad in 1990, there were 127 member countries. The Chess Olympiads were held at irregular intervals by FIDE until 1950; since then, they have been held regularly every two years.