German International Master (1950), International Arbiter (1951). Journalist and Chess writer, author of a series of chess books and textbooks. National Master in 1929. Rellstab was champion of the Großdeutschen Schachbundes in 1942.
Best results: Sopot 1936, 1st; Elster 1937, 1st-2nd; Berlin 1937, 1st-2nd; Stuttgart 1947, 1st; Bad Nauheim 1948, 2nd; Cuxhaven 1950, 1st-3rd; Viborg 1957, 1st; Madrid 1959, 3rd-4th; Hastings B 1972, 1st; and Bagneux Open 1973, 1st. He was also three times Champion of Berlin.
A participant in the Olympiads of 1936, 1950, 1952 and 1954.