October 16, 1941
: Tokyo (Toyoda) to Washington:
Although I have been requested by both the German and Italian Ambassadors in Tokyo to give to give them additional information on the Japanese-American negotiations, I have, in consideration of the nature of the negotiations, been declining to do so. However, early this month, following the German attacks on American merchant ships and the consequent (revival?) of the movement for the revision of the Neutrality Act, the German authorities demanded that the Japanese Government submit to the American Government a message to the effect that the Japanese Government observes that if the ROOSEVELT Administration continues to attack the Axis Powers increasingly, a belligerent situation would inevitably arise between Germany and Italy on the one hand and the United States on the other, and this would provide to reasons for the convocation of the duties envisioned in the Three Power agreement and might lead Japan to join immediately the war in opposition to the United States.
We have not, as yet, submitted this message because, in view of the Japanese-American negotiations, we found it necessary to consider carefully the proper timing as well as wording of the message. The German authorities have been repeatedly making the same request and there are reasons that do not permit this matter to be postponed any longer. While Japan on the one hand finds it necessary to do something in the way of carrying out the duties placed upon her by the Three-Power Alliance she had concluded with Germany, on the other hand, she is desirous of making a success of the Japanese-American negotiations. Under the circumstances, we can do no other than to warn the United States at an appropriate moment in such words as are given in my separate wire and as would not affect the Japanese-American negotiations in one way or another. This message is a secret between me and you. (Costello II)