Mr. Watson is correct. Green Hornet radio programs aired up to at least 1938 and earlier which still exist describe Britt Reid's chauffeur as his "Japanese valet." When international tensions subsequently increased, in 1939 or 40, the announcer's line was changed so the phrase became "trusted valet," which Kato remained throughout the majority of the the war years. In wartime programs his nationality was simply not mentioned in the show's opening or anywhere else during the program. After the war, in 1945, the opening was changed again, and announcers begin to refer to Kato as Britt Reid's "Filipino valet," and that is how openings were recorded till the end of the series. So the change didn't happen overnight, but in fact took at least five years, and the "Pearl Harbor" comment is an oversimplification, but the general idea is correct. The idea that this is all an urban legend arises mainly from the posting on urban legend website snopes.com, which is wrong about a lot of other things too and apparently more interested in perpetuating legends than publishing facts. Also, later syndications of Green Hornet radio programs consisted primarily of later broadcasts which would have for the most part included the description of Kato as Filipino. It is also correct that in the movie serials Kato, played by Keye Luke, is identified as Korean, and in the first serial Britt Reid and Kato discuss how they first met -- Britt saved Kato's life in Shanghai. In comic books published by NOW in the 1980s and authorized by the Green Hornet Inc., the situation is rectified and Kato's Japanese heritage fully acknowledged. Perhaps the truth of it all is that Mr. Reid told people his friend was something other than Japanese during the war to protect him from being taken to an interment camp.