Fred had thought that his Korean paternal grandfather was Japanese, until he discovered his origins on the show
Finding Your Roots with Henry Louis Gates, Jr. (2012). His grandfather, known as Masami Ehara-Kuni, was a dancer and choreographer who performed in Nazi Germany during the 1930s and 1940s, and was also possibly a spy for the Allies. Masami was actually born Pak Yeong-In in Ulsan, Korea, and had taken on a Japanese name and persona after attending a Japanese school during the Japanese occupation of Korea. There is a museum dedicated to Masami in Japan.
