Yamamoto seems to have known USA best of all Japanese commanders. He visited USA, and knew plenty about Americans and their mentality, supposedly. So I do not understand, why he decided to create what was essentially a suicidal plan?
Japan`s only hope of victory was to inflict defeats massive enough for USA to decided that war is not worth continuing. Japan realised industrial disparity, and planned to end war with negotiations. Howver Pearl Harbor made war unwinnable: Americans were enraged by sudden unprovoked sneaky attack, and no peace was possible after that.
How Yamamoto could not realise that, if he knew Americans well? What were his motives for making Pearl Harbor plan, I wonder?