Complex sentence: The Second World War came to the Soviet Union in June 1941, putting a stop to most organized chess for the next several years; but Alatortsev's solid pre-war results earned him an invitation to a strong event at Kuibyshev 1942.
Split into simpler sentences: The Second World War came to the Soviet Union in June 1941, putting a stop to most organized chess for the next several years. But Alatortsev's solid pre-war results earned him an invitation to a very strong event at Kuibyshev 1942.