What kind of proof do you want that the Admiral made this comment.?A note from Yamamoto? A tape recording? The comment was found in the files of Gordon Prange, on General MacArthur's staff, based on witness statements. Obviously, this war time comment would not have been made by the Admiral for general distribution. Nor, for similar reasons, would he put such a remark in writing. It was overheard by several attendees at a meeting with the Admiral. During WWI and for some time, thereafter, the comment was also very closely guarded by the U.S. Army as wartime intelligence.