Bidirectional Vulnerability Between East Asia and the Global Liner Shipping Network Under Typhoon-Driven Port Failures

East Asia is both the densest subsystem of the global liner shipping network and the home basin of its signature hazard, the typhoon. This study quantifies the relationship in both directions, as a stress test of the sustainability of maritime connectivity, across Alphaliner-based reconstructions of the 2017 and 2021 networks that cover every port with at least one scheduled liner service. A Typhoon Vulnerability Index built from validated IBTrACS exposure, betweenness sensitivity, and national adaptive capacity scores 330 and 272 affected ports. The risk geography anchors in East Asia in both years and more strongly in the second, as the regional share of affected ports is 29 percent in 2017 and 44 percent in 2021, the 2017 top five are all East Asian, and the 2021 top four are all Chinese, led by Shanghai. Removing every indexed typhoon port in descending risk order destroys 47.5 and 41.3 percent of baseline efficiency. Equal-sized random removals destroy a similar share at the end, so the information of the hazard ordering lies earlier and elsewhere, in early losses that run about forty percent above the random expectation, in seven of the ten earliest failures being invisible to degree screening, and in the identity of the removed ports, while equal-depth-degree targeting destroys far more at every stage. An East Asia-only attack reproduces a third of the full attack’s damage in 2017 and half in 2021. Under one fixed baseline, East Asia carries 23.8 and 24.6 percent of global efficiency before the attack and its survivors retain 7.1 and 3.6 percent after it. On the evidence of these two years, the typhoon corridor is a jointly held systemic asset, its protection is a problem shared by the three economies, and the bidirectional accounting gives sustainable maritime transport a measurable resilience baseline under a warming climate.