Japan Times and Advertiser, Tuesday 13th May 1941 (Evening Edition Page 4)

Services for Sumo Fans

    In the pandemonium that reigns throughout the Kokugikan arena immediately after every important bout, it is an impossibility to hear the decision and other important details of the results, especially when one is seated way up in "nigger heaven". Hence, for the use of these customers, special audiphones have been installed at a minimum charge of 30 sen per day.