In the Indo-Pacific, navies play a major role in shaping a balance of power that generates deterrence effects. The roles and strategies of the Royal Australian Navy (RAN) and the Japan Maritime Self-Defense Force (JMSDF) in the Indo-Pacific are crucial to this deterrence. 

When we think about power in international relations, it’s easy to imagine armies clashing on battlefields, tanks rolling across borders, and soldiers digging in along frontlines. But in the Indo-Pacific—a region dominated by the vast expanses of the Pacific and Indian Oceans—power isn’t wielded by armies on land. Instead, it’s the naval forces of the region’s key players that are defining the balance of power. As these nations jockey for influence and security, it’s becoming increasingly clear that traditional, land-based concepts of power don’t fully apply. In the Indo-Pacific, it is sea power that holds the reins, and the strategies employed by these navies are what keeps potential conflicts in check. 

The concept of the balance of power isn’t just academic jargon; it’s a practical reality that has kept the peace in many parts of the world. When states perceive that there’s a rough equivalence in military capabilities, they’re less likely to risk war because the outcome is uncertain and the costs are potentially catastrophic. In regions like Europe, this balance is maintained by armies stationed along borders, ready to defend territory. But the Indo-Pacific’s unique maritime geography means that this kind of land-based deterrence isn’t feasible. Instead, the nations of this region rely on their navies to create and maintain a balance of power that deters aggression and preserves stability. 

Naval deterrence, however, is a more complex game than land-based defence. On land, the goal is relatively straightforward: hold territory, or take it from the enemy. But at sea, the rules are different. The oceans cannot be occupied or controlled in the same way land can be. Fleets cannot maintain a constant presence across vast maritime areas, and they need to return to port for supplies and rest, making it impossible to “hold” the sea as you might hold a piece of land. This is where naval strategy becomes crucial. Power at sea isn’t just about the number of ships you have, but how you use them—where they’re deployed, what missions they undertake, and how they’re supported. 

This strategic complexity is especially important in the Indo-Pacific, where the vastness of the ocean and the importance of key maritime trade routes make sea power a decisive factor in regional security. Unlike the relatively confined waters of the Mediterranean or the North Sea, the Indo-Pacific encompasses two of the world’s largest oceans, connecting some of the world’s most important economic hubs. The scale of the region means that no single navy, not even that of the United States, can fully dominate the entire area simultaneously. Instead, navies in the Indo-Pacific must carefully choose where to deploy their forces, concentrating them in key areas where they can exert the most influence. 

The Royal Australian Navy (RAN) and Japan’s Maritime Self-Defense Force (JMSDF) are not the largest navies in the world, but they play important roles in shaping the balance of power in the Indo-Pacific. Both countries have developed naval strategies that reflect their geographical realities, their strategic interests, and their relationships with other regional powers, particularly China. 

Australia’s 2024 National Defence Strategy makes it clear that Canberra is fully aware of the growing maritime capabilities of China, a country whose naval ambitions are rapidly expanding. Faced with a significant capability gap, Australia has wisely adopted what it calls a “Strategy of Denial.” Rather than attempting to match China’s naval power ship for ship, Australia is focusing on preventing China from controlling key sea routes in Southeast Asia and the South Pacific—regions that are critical to Australia’s security and economic interests. 

This denial strategy is evident in the RAN’s increased operations in these areas, including hosting large-scale exercises like Talisman Sabre, which brings together forces from Australia, the United States, and other regional partners. These exercises not only demonstrate Australia’s commitment to defending its maritime interests but also serve as a signal to potential adversaries that any attempt to dominate these waters will be met with significant resistance. The RAN is also investing in new capabilities, such as the acquisition of nuclear-powered attack submarines (SSNs) through the AUKUS pact. These submarines, which can operate for extended periods without surfacing, will greatly enhance Australia’s ability to carry out its denial strategy, providing a stealthy and persistent presence in key maritime areas. 

Japan’s approach, while similar, is shaped by its own unique strategic challenges. The JMSDF focuses heavily on denying Chinese influence in the East China Sea and the South China Sea—two areas that are vital not only to Japan’s economic security but also to its territorial integrity. The East China Sea is home to the disputed Senkaku/Diaoyu Islands, where tensions between Japan and China have simmered for years. Meanwhile, the South China Sea is a critical corridor for Japan’s energy imports, with around 80 percent of Japanese oil transiting through these waters. 

Japan has not explicitly adopted the term “denial strategy,” but its actions speak louder than words. The JMSDF has significantly increased the frequency and scale of its naval exercises, often in partnership with the United States, to demonstrate its ability to operate effectively in these contested waters. For instance, the recent Keen Sword exercise, a biennial naval drill between the US Navy and the JMSDF, was held in the East China Sea, sending a clear message to Beijing that Japan will defend its interests. Additionally, Japan’s annual Indo-Pacific Deployment, which includes visits to Southeast Asia and other strategic regions, further underscores its commitment to maintaining a presence in key maritime areas. 

The strategic focus of both the RAN and the JMSDF highlights the critical role that navies play in maintaining the balance of power in the Indo-Pacific. In this region, where vast oceans separate states and connect economies, sea power is the most effective means of projecting influence and deterring conflict. The openness and vastness of the maritime domain make it hard for any one navy to dominate, so the ability to deny control to an adversary becomes a key aspect of regional security. 

As the Indo-Pacific continues to emerge as the central theatre of global strategic competition, it’s crucial to recognise that the balance of power here is not about sheer numbers or brute force. Instead, it’s about strategy—specifically, how to allocate naval assets to control or deny control over key maritime areas. The RAN and JMSDF, through their carefully calibrated denial strategies, are playing a vital role in preserving peace and stability in this increasingly contested region. Their actions remind us that in the Indo-Pacific, it is not armies, but navies, that hold the key to the balance of power. 

Dongkeun Lee is a PhD candidate at the Strategic and Defence Studies Centre (SDSC), The Australian National University, and a reservist officer of the Republic of Korea Navy (ROKN). Before Dongkeun joined SDSC as a PhD candidate in February 2022, he served 3 years at the ROKN as an intelligence officer.

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