Kent sent me some photos, and one was the same photo I had found–of a performance of Japanese music in Topaz that included his mother playing shamisen.
Tama met her husband at Topaz and they later married. After the War, determined to assimilate as quickly as possible, her husband advised her never to play the Japanese instruments again, nor to speak in Japanese. This was fairly common in Japanese American families who had been incarcerated for three-and-a-half years: to put aside their cultural practices in order to be accepted. Tama took up the piano instead—and her koto and shamisen sat untouched for almost 80 years.