China's economy is dependent on foreign trade, 90 percent of which travels by sea. China's near seas — the Yellow Sea, the East China Sea and the South China Sea — are bounded by what Chinese strategists call the "First Island Chain," a series of islands (many of which are controlled by U.S. allies) that stretches from Japan to the Philippines to Indonesia. To reach ports on China's eastern coast, seaborne trade from the west must pass through maritime chokepoints such as the Strait of Malacca (through which 82 percent of China's crude oil imports passed in 2013). Passage through these maritime chokepoints is secured by another country: the United States, the world's dominant naval power.
The geographic enclosure of China's near seas would make it relatively easy for an adversary to disrupt or interdict Chinese trade. China faces many challenges in developing the ability to project sufficient naval power to safeguard seaborne trade as it passes through distant chokepoints. Instead, China must rely on the United States to provide security of the sea-lanes. Although maritime security is ostensibly a public good, China worries that, as a potential peer competitor to the United States, it will not always be able to rely on the United States to protect its shipping.
U.S. war planners have certainly not ignored China's geographic vulnerability. A 2015 Department of Defense report to Congress on China mapped out chokepoints for Chinese energy imports, a move unlikely to have gone unnoticed in Beijing. In the case of a war between the United States and China, many U.S. strategists favor imposing a distant blockade of Chinese waters. Although the U.S. Navy has unchallenged supremacy over the open ocean, resource constraints — and the risks posed by China's anti-ship capabilities in its near seas — suggest that U.S. forces would concentrate on blocking the chokepoints.
The Belt and Road Initiative aims to mitigate the risk of maritime interdiction by constructing transit routes along six economic corridors. In these corridors, China will enhance existing transportation networks, construct new roadways and build intermodal transport hubs and energy pipelines. Alongside these projects will come investment in attendant infrastructure, including power plants and communications technology such as fiber-optic cables. China will not be starting from scratch — it has already built up a patchwork of infrastructure across Eurasia, and much of the Belt and Road work will simply link existing segments of road and railway.
