Claim: Joao de Souza Mendes was a seven-time chess champion, playing in the Portugese Chess Championship 29 times, and playing twice for the Chess Olympiads, a biennial chess tourament which attempted to become  part of the Olympic games in 1924, but failed.
Evidence: He played for Brazil in Chess Olympiads at Buenos Aires 1939 and Helsinki 1952. Born in the Azores, Portugal, Souza Mendes played in the Brazilian Chess Championship 29 times, winning in 1925 (the first year the tournament was held), 1928, 1929, 1930, 1943, 1954, and 1958.