If the Japanese had let Yamamoto run the war according to his vision without constant restraint from senior "battleship admirals" and the Army (Tojo), I'm convinced his understanding of industrial capacity and the crucial importance of logistics would have led to the choking off of Hawaii and then Australia. He also understood the strategic importance of aircraft and submarines in a resource war in the Pacific. If Kido Butai had succeeded in destroying the American carriers at Pearl, and if it had been commanded by a bold, aggressive, aviator admiral, it could have stuck around Oahu a while longer and taken out the important oversights the first raid missed. Fueling and repair facilities, the submarine base, and long range patrol aircraft (besides the carriers of course) were what sustained the American war effort for the first few months of the war. Yamamoto understood this. A couple more waves of attacks could have eliminated these and left Hawaii essentially defenseless and difficult to supply. IJN doctrine wasted their extensive submarine fleet in a fruitless search for capital ships to sink, rather than the scouting and supply-line strangling which could have been their true value. Yamamoto understood this, but was powerless to change it. GG correctly points out that the majority of American shipbuilding and ordnance manufacturing was East Coast based. Aircraft manufacture, on the other hand (at least of the critical types) was concentrated In California and Washington. I know Bell, Chance Vought, Curtiss, Grumman, Martin, and Republic were East, but Boeing, Consolidated, Douglas, Lockheed, North American, and Northrop were all within easy air raid (or even battleship gun) range of the Pacific. With (as GG suggests) toe holds in Panama and the resource-rich American west coast a lot of the Japanese supply line dilemma would be eliminated, and (as the US later did) bypassed garrisons could be ignored and allowed to starve. With no safe haven Naval bases on the entire west coast, and Hawaii, the Philippines, and Australia gone, we would have been stymied in the Pacific and fighting a defensive war on the mainland. In December 41 and January 42 we would have been too shocked, demoralised, and disorganized to prevent the Japanese from making rapid territorial gains in the west and turning some of our own industrial might against us. They could have withdrawn most of the Kwantung Army from China and shipped them to California. Without foreign military aid neither Chiang nor Mao was any threat to Japan. The US would have had to concentrate its resources at home, leaving Britain and Russia vulnerable. If the Japanese forays into the Indian Ocean had been conducted with a conquest mentality rather than just raiding, India would have fallen, if treated properly, that huge suppressed population would have enthusiastically joined the "Greater East Asia Co-Prosperity Sphere" and kicked the "white oppressors" out of Asia entirely. So there you have it; Japan sitting securely on top of a major chunk of the world's resources, with no significant opponents in position to threaten its resources, its logistics, or its industry.