How delay changes Japan's attrition doctrine

The assessment places the last practical opportunity to prevent war before Kido Butai leaves for Pearl Harbor. Yonai could use a delay to modernize the services, while the United States would continue its own expansion under the Two-Ocean Navy program. Japanese doctrine envisaged wearing down an advancing enemy before the final decisive battle. A larger American fleet could fit the Japanese expectation that numerical confidence would encourage an incautious advance. American war games, however, had already examined what Japan wanted its opponent to do. Japan's planners still depended on attrition as their route to victory, so additional preparation would leave that strategic dependence unresolved.