China’s military modernization has allowed it to take a more assertive position on the territorial disputes it currently has with Japan and its Southeast Asian neighbors. The South China Sea (SCS) dispute is a clear example. Meanwhile, Japan is normalizing its military status to play a more proactive security role in the region. Japan’s normalization process has been greatly influenced by China’s growing military capabilities as it fears that China could pose a threat to its sea lanes of communications. Although Japan does not have territorial claims in the SCS, it regards the SCS as a strategically vital area. It is this particular concern that has brought Japan into the current territorial disputes in the SCS. This thesis analyzes how Japan has tried to forge partnerships with Southeast Asian countries in the form of foreign aid and the provision of military equipment and training that can potentially offset China’s assertiveness.