Leo was seven years old when Germany invaded Poland in September 1939. Before the war, Leo's father was a mathematics teacher and member of the Bialystok City Council. Fearing arrest, Leo's father fled Bialystok for Vilna just before the German occupation. Leo and his mother eventually joined his father in Vilna. After the Soviets occupied Vilna, Leo's father obtained transit visas to Japan. The family left Vilna in December 1940, traveled across the Soviet Union on the Trans-Siberian Express, and arrived in Japan in January 1941. Leo's family obtained visas for the United States and immigrated in April 1941.
The train to Wilno [Vilna] was such that you couldn't get on. People were standing in the aisles. There was no sitting room. Because I was a child, uh, someone gave me a seat, uh, on some boxes near a window, so I could actually watch, uh, from the window. But my mother stood the entire...it's...it's a couple hours' trip in normal times. It took the full night to do so, in fact, more than the night. We left...it was probably about six in the evening and did not arrive till nine the next morning. And during the course of that, uh, ride, the train would stop for what seemed like hours, some places. And there would be shouting and sometimes there would be gunfire. And, uh, in all of the...all of the accoutrements of war around us, and yet, uh, it kept moving.