Kinmen and Matsu: The Offshore Islands That Taiwan Still Holds Three Miles from China
Kinmen Island sits approximately 3.5 kilometers from the Chinese city of Xiamen. On a clear day, residents of Kinmen can see the skyline of a Chinese city of five million people across a strip of water narrower than the distance between Manhattan and Staten Island. Taiwan has administered Kinmen since 1949, when Nationalist forces successfully repelled a PLA amphibious assault that, if successful, might have changed the entire trajectory of the civil war’s outcome. The island has been shelled, blockaded, and fought over. It is still Taiwanese. Its continued existence as a piece of Taiwanese territory three kilometers from the Chinese mainland is one of the more remarkable geopolitical facts of the twentieth and twenty-first centuries.
The First and Second Taiwan Strait Crises — 1954-1955 and 1958 — both centered on Kinmen and Matsu, the two main offshore island groups that Taiwan retained after the communist victory on the mainland. The 1958 crisis involved a sustained PLA artillery bombardment of Kinmen that lasted months, with the United States deploying carrier forces to the region and considering whether to provide Taiwan with nuclear-capable weapons systems to defend the islands. The Eisenhower administration decided against the nuclear option and instead established the logistical and convoy arrangements that sustained Kinmen under bombardment. The bombing eventually settled into a ritual — PLA artillery fired on odd-numbered days, Taiwanese artillery responded on even-numbered days — a formalization of conflict that lasted until 1979.
The strategic significance of the offshore islands in a contemporary Taiwan contingency is contested. The islands are not necessary for Taiwan’s core defense — they sit on the Chinese side of the strait’s main navigational channel and contribute little to the coastal defense of Taiwan proper. Their primary value is political and symbolic: they are territory that Taiwan holds within sight of the Chinese mainland, a persistent physical demonstration of a political reality that Beijing finds intolerable. Giving them up in a crisis — or failing to defend them — would be perceived as a dramatic retreat that could affect morale, domestic politics, and international perceptions of Taiwanese resolve.
The military problem of defending Kinmen and Matsu in a serious PLA operation is severe. Both island groups are within artillery range of the mainland — not just the 1950s artillery that bombarded them for twenty years, but modern precision-guided systems that can strike specific structures rather than general areas. They can be cut off from Taiwan proper by naval interdiction of the relatively short but contested strait between the islands and Taiwan’s western coast. Their garrison forces, however well-equipped, would be fighting in a surrounded position without the depth of terrain that meaningful defense requires.
China has periodically used the offshore islands as pressure instruments below the threshold of military attack. Restrictions on fishing in the surrounding waters, interference with ferry services that provide the islands’ civilian connection to Taiwan, and coast guard operations that Taiwanese administration officials have described as harassment have all been used to demonstrate Chinese capacity to impose costs on the islands without escalating to military action. The incidents are calibrated below the threshold that would require a military response while being above the threshold of normal competitive behavior.
For Taiwan’s broader defense calculus, the offshore islands present a resource allocation problem. Forces and equipment devoted to defending Kinmen and Matsu are not available for the defense of Taiwan proper. The question of whether to reinforce the islands in a crisis, accept their loss as the price of concentrating defense of the main island, or attempt to negotiate their status as part of a broader cross-strait arrangement has no good answer and reflects the broader impossibility of Taiwan’s strategic position: defending everything means defending nothing adequately, and prioritizing Taiwan proper means accepting losses that have political costs that the defense rationale cannot fully offset.
Three kilometers of water. Seventy-five years of contested sovereignty. The offshore islands are not incidental to the Taiwan story. They are its physical condensation.