Answer: Internment camps.
In May of 1942, the Kobayashi family was evacuated under Executive Order 9066 to the Tanforan Assembly Center, a former race track in San Bruno, California. The executive order authorized the internment of Japanese Americans who were “in military areas in such places and of such extent as he [the Secretary of War] or the appropriate Military Commander may determine, from which any or all persons may be excluded, and with respect to which, the right of any person to enter, remain in, or leave shall be subject to whatever restrictions the Secretary of War or the appropriate Military Commander may impose in his discretion.” (The excluded areas included Oregon, Washington, California, and parts of Arizona. Had the Kobayashis not lived in California at the time, they likely would not have been removed to any of the internment camps.) After Tanforan, the Kobayashis were transferred to a relocation center in Topaz, Utah.
One of the Kobayashi children, Sumiko, was among the young Japanese Americans allowed to leave the camps in order to attend college through the help of the National Japanese American Student Relocation Council. She went on to serve with the Philadelphia Chapter of the Japanese American Citizens League (JACL), and she became a prominent figure in the movement to provide redress for Japanese Americans removed to internment camps during World War II. She remains active in a number of beneficial organizations, both in the Philadelphia area and nationally.
Among HSP's collections are several that document the Japanese American experience during World War II, including the Susumu Kobayashi papers (MSS071), the Sumiko Kobayashi papers (MSS073 and MSS073A), the Saburo and Michiyo Inouye Papers (SC163 and PG 224), and the Shigezo and Sonoko Iwata papers (MSS053).