Hormuz Crisis Forces Japan, South Korea to Reassess Maritime Strategy

Strategic Vulnerability Exposed

The recent blockade of the Strait of Hormuz has unsettled Japan and South Korea, underscoring their heavy reliance on open sea routes for critical supplies. Essential imports such as energy, food, and raw materials flow through this vital waterway, which has now become a focal point of geopolitical concern. The prolonged conflict between the US and Iran has disrupted global oil and gas trade, with lingering effects expected even after a potential agreement is reached.

China’s Growing Influence in the South China Sea

The South China Sea has emerged as a key area of tension, especially since China began establishing military presence on contested islands in 2012. These islands now serve as hubs for airfields and defensive structures, through which an estimated $3.36 trillion in annual global trade transits. Analysts warn, however, that the region’s vulnerability is not confined to this single location.

“The sea lanes serving Japan and South Korea form a continuous corridor, with the South China Sea and Taiwan Strait closely linked,” said William Yang, a Taiwan-based expert at the International Crisis Group. “Even if ships pass through the South China Sea safely, they still must navigate the Luzon or Taiwan approaches to reach Northeast Asia.”

Yang emphasized that in a crisis involving Taiwan, these northern routes could rival the South China Sea in significance. “It is more accurate to view the region as a connected maritime battlespace extending from Southeast Asia to the Taiwan Strait,” he noted. “Strategic shocks from any disruption here could ripple across entire economies.”

US-Iran Tensions and Regional Implications

Japan and South Korea now face the reality that a similar crisis closer to home—such as in the South China Sea or over Taiwan—could be far more devastating. “Sea lanes are absolutely vital to both nations,” explained Joseph Kristanto, a maritime security analyst at Singapore’s S. Rajaratnam School. “If these routes were blocked for an extended period, the consequences would extend beyond just shipping delays.”

Kristanto highlighted that energy prices would soar, production levels could falter, and food and input costs would climb. “Both economies would experience a major strategic shock,” he said. The situation also reflects broader concerns about the US’s reduced military presence in the Indo-Pacific, with China capitalizing on this shift.

Geopolitical Moves and Energy Security

Last week, Beijing raised objections after a Japanese naval vessel transited the Taiwan Strait, an action Tokyo defended as a demonstration of “freedom of navigation under international law.” Meanwhile, a Reuters report noted China’s deployment of ships and floating barriers near the South China Sea’s disputed area with the Philippines. This coincides with the US relocating its aircraft carrier groups to the Middle East.

In response to potential supply risks, Japan and South Korea have taken steps to secure energy sources. Last month, Korea Gas Corporation and JERA, the world’s largest LNG importers, signed a framework to enhance resilience. The agreement includes mutual delivery swaps and analysis of alternative supply chains, reflecting their shared dependence on uninterrupted maritime trade.