peacetime), the fleet would sail to the western Pacific to relieve American forces in Guam and the Philippines. Afterwards, the fleet would sail north for a decisive battle against the Imperial Japanese Navy's Combined Fleet and then blockade the Japanese home islands. The strategy was in keeping with the theory of Alfred Thayer Mahan, a doctrine to which every major navy subscribed before World War II in which wars would be decided by engagements between opposing surface fleets (as they had been for over 300 years). Following the 1933 Operations IV Wargame, which resulted in defeat for a hypothetical blue fleet meant to symbolize a US Philippine relief force, War Plan Orange was revised to account for a more steady, methodical advance in order to take Japanese strongpoints in the Marshall Islands. This was done in accordance to observations that both stretched logistical capacity in the "through ticket to the Philippines" strategy, and inability to repair damaged vessels, allowed Japan to gain command of the sea via the neutralization of the US battle line force. Despite this, the strategy followed by the U.S. in the Pacific War differed little from Rodgers' concept from 1911: a "leapfrog" campaign to conquer the Marshalls and Carolines (held by Japan before the war); liberation of the Philippines; and blockade. Absent was the "decisive battle" of Mahan, and of Japanese planning. Japanese plans The Imperial Japanese Navy developed a counterplan to allow the U.S. Pacific Fleet to sail across the Pacific while using submarines and carrier attacks to weaken it. The Japanese fleet would then attempt to force a fleet action against the weakened U.S. fleet in a "decisive battle area", near Japan (see Kantai Kessen), also in line with Mahanian doctrine, which Japan had enthusiastically embraced. It was the basis for Japan's demand for a 70% ratio (10:10:7) at the Washington Naval Conference, which was considered necessary to provide Japan superiority in the "decisive battle area" (taking into account that the U.S. had naval commitments in other theaters, while Japan did not). It was also the basis of the United States' insistence on 60%, which amounted to parity. Outcomes Actual events generally followed the plan. Although carrier battles and the use of airplanes and submarines overshadowed surface action, the "leapfrog" campaign played out largely as anticipated. The Imperial Japanese Navy, obsessed with the "decisive battle" doctrine, ignored the vital need for defense against submarines.