LAURENCE REES: From November 1941 the Americans strongly believed they were going to be the victim of a Japanese attack. So how then is it possible that Pearl Harbour comes as a surprise?

AKIRA IRIYE: Because the Americans knew that Japan was going to start the war, but they did not have a clear idea of where Japan was going to strike. I think they had a pretty good idea of when it was going to happen.  They were reading some of these cables and they had suspected it either on the 7th of December or around that time, but I think they had thought in terms of the Japanese attacking the British in Singapore, possibly even the Philippines, but there was no expectation that Pearl Harbour would be the target or one of the targets because they had not read this naval code apparently exchanged by the Japanese military that Pearl Harbour was being targeted for attack. I think that’s the story.

LAURENCE REES: BUt wouldn’t they have put all their bases on very, very high alert given the worries?

AKIRA IRIYE: They had been. I think all the commanders in Hawaii and Philippines had been put on alert but the attack itself had not been anticipated. I think that’s the story. More recently people have been saying that they had read some of these secret command messages and the Japanese had read American messages and things like that, but I think the simple line still seems to be that even though the Americans expected a Japanese attack, they had not expected the kind of attack from air carriers on Pearl Harbour in the way that it came. Of course, there is a conspiracy theory that Roosevelt knew all along about it and that he didn’t want to tell the Hawaiian commanders about it, but I don’t think 98 percent of military historians would buy that even in Japan or in the United States.

LAURENCE REES: So to what extent was the reason that the Americans were surprised at Pearl Harbour simply because they were amazingly complacent?

AKIRA IRIYE: Nobody had ever attacked the United States across the ocean and I think the picture at that time must have been that Japan was quite likely going to go into the Philippines. They [the USA] had war plans for defence with the Philippines going back to the turn of the century, but I don’t think they had prepared any kind of a systematic war plan involving Hawaii. And they had felt that by putting the bulk of the US fleet in Hawaii in 1940 this would prevent Japan’s attack. The US fleet would be so formidable that they could not conceive of Japan crossing the Pacific all the way and assaulting the US Navy. I think that must have been just beyond comprehension.

Now it looks easy, in retrospect, to say they should have thought about it. They had not even rounded up Japanese residents there as spies or enemies. Basically this was a case of complacency perhaps, that in all their war plans and everything else they had just not quite paid enough attention to the defence of Hawaii.

LAURENCE REES: And was there also an element of racism, of thinking the Japanese weren’t capable of something like this because of the nature of who they were?

AKIRA IRIYE: Whether racism or some sense of viewing other countries as not as capable as the Americans; probably it’s that. I think that it’s not so much racism as simply the ignorance of Japan. Ignorance of the Japanese mentality, maybe it’s that. They may not have been quite attuned to the kind of mentality that had emphasised bold action, death in battle, that kind of thing, there is an honourable saying: to undertake something even when that thing looks very irrational.  This is the Japanese attitude throughout the war, you try something and you commit suicide or you engage in suicide bombing raids, things like that, regardless of consequences or whether it’s going to work or not. There’s no rational thinking behind that. Of course with the Pearl Harbour attack you would say it was a very rational strategy, which it was, but there is this element of adventurousness, that things might not work, but they would try it in any event and see what happened. I think there is that kind of mentality which may have been something which, to the more rational American mind, would have been rather hard to imagine.