Although China has been involved in twenty-three territorial disputes with its neighbors since 1949, it has used force in only six of them. The strength of a state's territorial claim, defined as its bargaining power in a dispute, offers one explanation for why and when states escalate territorial disputes to high levels of violence. This bargaining power depends on the amount of contested land that each side controls and on the military power that can be projected over the entire area under dispute. When a state's bargaining power declines relative to that of its adversary, its leaders become more pessimistic about achieving their territorial goals and face strong preventive motivations to seize disputed land or signal resolve through the use of force. Cross-sectional analysis and longitudinal case studies demonstrate that such negative shifts in bargaining power explain the majority of China's uses of force in its territorial disputes.