China's assertiveness in the East and South China Sea (ESCS), complemented with paradoxical behavior on promoting international maritime cooperation, has left many to conclude that Beijing uses a dual strategy. To expand China's foreign policy's interpretation, we present an alternative approach with a neoclassical realist analytical framework to supplement the maritime security perspective. By accommodating domestic political changes, we explain the causal process that leads to China's maritime ambiguity and illustrates how it shaped the theater of conflict in ESCS. Understanding the disputes from the framework of unitlevel factors such as state-especially in China's local political dynamics-can bring a novel dimension to the discussion. We argue China's military reform to build a "true maritime power" ( 海洋强 國 ) through the utilisation of the grey zone strategy via the China Coast Guard (CCG) plays a significant role in intervening against international politics' dynamic to deter the possibility of high-intensity conflict. Thus, the maritime security of rival country is more focused on how to deal with (1) non-traditional challenges in the sea such as piracy and (2) intergovernmental confidence building through the means of white hull diplomacy-while countering China's ambition on claiming the rights and interests in ESCS 'under the threshold of war.'