It is my understanding that Yamamoto told the Imperial Staff that attacking the United States would be a disastrous blunder because he had studied and traveled throughout the US as a junior naval officer and saw what we were capable of industrially. But they told him to plan for attack anyway and he dutifully did so.
“It is my understanding that Yamamoto told the Imperial Staff that attacking the United States would be a disastrous blunder because he had studied and traveled throughout the US as a junior naval officer and saw what we were capable of industrially.”
Both Yamamoto and the German general Eric von Manstein both counseled their governments on the American industrial ability to retool. The prevailing wisdom of industry in Germany and Japan was that expensive retooling to produce new products (in particular automobiles) every year was foolishness on the part of the Americans. American firms were ridiculed for producing ‘toys’ and frivolous products like washing machines by both the German and Japanese commands and their analysts. Yamamoto and Manstein understood the threat.
German and Japanese factories would produce a particular product or vehicle for ten to fifteen years before retooling. And then the retooling of a factory would shut the factory down for months at a time.
American firms understood that consumers desired new (and improved) products and retooling to produce new things became customary and so practiced that downtime between product runs was sometimes measured in hours. Auto plants could retool in a few days and had the process down to a science. The last vehicle of a model year would move down the line and the line was pulled up and replaced behind it.
Consequently when the war started auto plants retooled and started producing planes and tanks in as little as a week. The company that produced Erector Set toys rapidly switched to producing Thompson submachine guns. A Dodge plant took only a week to switch from producing cars to producing B-24 bombers.
And Maytag cleverly switched from producing washing machines to producing gun turrets for aircraft and armored vehicles. The initial runs of gun turrets actually used up supplies of washing machine tubs for gunner seating!
In short the US economy took less than six months to completely refocus on war production. It was an economic ability that the Germans and Japanese dreadfully underestimated.
I think he was pushing pretty hard for this attack, even though he was well aware that Japan stood no realistic chance against the US if he failed.
I think it's popular in American lore to portray the Japanese as either stupid or naive with regard to their decision to attack Pearl Harbor, and there is simply no evidence for this.
Japan's plans for Southeast Asia were simply never going to be accepted by the US, and they were well aware that conflict was almost inevitable. The only question was which approach held the most realistic chance of success.
And yes, Yamamoto had studied in the US; as I pointed out earlier, he also predicted that if we could reach Japan with our bombers, we would simply drop incendiaries on them. (Japan's vulnerability to incendiary bombs was no secret to anyone in the run-up to the Second World War.) He was quite prescient about what the US was capable of, both morally and militarily.
If today A Chinese Naval officer did the same what would he report back?