This document discusses why Japan initially attacked the US and was initially successful in the Pacific, but ultimately lost. It summarizes:
1) Japan attacked the US due to its expanding influence in the Pacific and Asia, and a belief the US was unprepared for war.
2) Japan was initially successful because the US and allies were unprepared, Japanese forces were highly motivated and brutal, and local populations welcomed them as liberators from Western influence.
3) Japan ultimately lost because of the immense economic and military power of the fully mobilized US, Japan's lack of resources, the US strategy of island hopping, effective submarine warfare and intelligence that atomic bombs could avoid massive casualties of an invasion of the Japanese