Japanese Admiral Isoroku Yamamoto is portrayed at the very end of the 1970 film Tora! Tora! Tora!, and in the 2001 film Pearl Harbor, as saying after his attack on Pearl Harbor, "I fear all we have done is to awaken a sleeping giant and fill him with a terrible resolve.".....
Regardless of the provenance of the quote, Yamamoto believed that Japan could not win a protracted war with the United States. Moreover, he seems to have believed that the Pearl Harbor attack had become a blunder — even though he was the person who came up with the idea of a surprise attack on Pearl Harbor.
It is recorded that "Yamamoto alone" (while all his staff members were celebrating) spent the day after Pearl Harbor "sunk in apparent depression". He is also known to have been upset by the bungling of the Foreign Ministry which led to the attack happening while the countries were technically at peace, thus making the incident an unprovoked sneak attack that would certainly enrage the enemy.
http://en.wikipedia.org/wiki/Isoroku_Yamamoto%27s_sleeping_giant_quote
