During the Cold War, the Japanese Maritime Self-Defense Force (JMSDF) was heavily focused on defending Japan from a Soviet invasion and ensuring sea lines of communications (SLOC) were available for U.S. naval forces in the event of a major conflict. After the Cold War, the JMSDF had to adopt new missions based on the constantly changing threat environment. This thesis assesses how well the JMSDF responded to a variety of threats to Japan during each of the three decades since the end of the Cold War. The main chapters look at the threats Japan faced each decade and then how JMSDF equipment and policy changed as a result of the identified threats. The research suggests that the JMSDF usually falls in the middle of the spectrum and adequately meets defense requirements. It also shows that there were times where the JMSDF was not prepared or was over prepared, but adjustments were made to bring the JMSDF back to the middle ground.http://archive.org/details/japanesemaritime1094561383Lieutenant, United States NavyApproved for public release; distribution is unlimited