To add to that, Japanese leaders aren't so keen on visiting the Pearl Harbor site either. Though their emperor has now spent a visit there: http://www.telegraph.co.uk/news/worldnews/asia/japan/4918516... Neither country has come up with a formal apology.
"The attack took place before any formal declaration of war was made by Japan, but this was not Admiral Yamamoto's intention. He originally stipulated that the attack should not commence until thirty minutes after Japan had informed the United States that peace negotiations were at an end.[citation needed] The Japanese tried to uphold the conventions of war while still achieving surprise, but the attack began before the notice could be delivered."
on the other hand, making the schedule that tight increases the risk that your message doesn't get delivered in time.
"In 1999, however, Takeo Iguchi, a professor of law and international relations at International Christian University in Tokyo, discovered documents that pointed to a vigorous debate inside the government over how, and indeed whether, to notify Washington of Japan's intention to break off negotiations and start a war, including a December 7 entry in the war diary saying, "our deceptive diplomacy is steadily proceeding toward success." Of this, Iguchi said, "The diary shows that the army and navy did not want to give any proper declaration of war, or indeed prior notice even of the termination of negotiations ... and they clearly prevailed."
I don't see how one can conclude that "clearly prevailed". The message apparently wasn't 100% clear, but there was a message.
Wikipedia also says the U.S. had broken the code used to encrypt that message. That makes it unlikely that there was a second super-secret message "make sure the next message arrives late"
(Of course, this is all playing historian from a single Wikipedia page, the occasional TV program, and a tiny bit of other reading over the years)
Even a simple sentences can be translated to have may different meanings. This came up again when the Americans had trouble translating the statements the Japanese made after the Hiroshima bombing.