Semyon Bychov, the Russian-born music director of the Czech Philharmonic, opens the new season with a single work. The genesis and early performance history of Dmitri Shostakovich’s 75-minute Symphony No. 7, the “Leningrad”—including its wartime New York premiere in a broadcast led by Arturo Toscanini—are the stuff of a John Le Carré novel. Acclaimed as a symbol of resistance to totalitarianism, the work won Shostakovich as shining an accolade as any the United States had to offer back in the day: a cover story in Time magazine. The sequence no one forgets occurs in the first of four movements, an Allegretto the composer originally called “War.” Accompanied by the snare drum, there’s a 22-bar “invasion” march, repeated (with varying orchestration) a mesmerizing dozen times. (In Boléro, Ravel pulled the plug after eight repeats.) —M.G.