[1]Vermont Royster offers a possible origin to the phrase attributed to Napoleon, "China is a sickly, sleeping giant.

Williams, in turn, has stated that Larry Forrester, the screenwriter, found a 1943 letter from Yamamoto to the Admiralty in Tokyo containing the quotation.

Randall Wallace, the screenwriter of the 2001 film Pearl Harbor, readily admitted that he copied the line from Tora!

It is recorded that while all his staff members were celebrating, "Yamamoto alone" spent the day after Pearl Harbor "sunk in apparent depression".

In The Reluctant Admiral, Hiroyuki Agawa gives a quotation from a reply by Yamamoto to Ogata Taketora on January 9, 1942, which is similar to the famous version: "A military man can scarcely pride himself on having 'smitten a sleeping enemy'; it is more a matter of shame, simply, for the one smitten.

"[5] The other common quotation attributed to Yamamoto predicting the future outcome of a naval war against the United States is, "I can run wild for six months... after that, I have no expectation of success".