The essay examines the Cassel mining agreement in Guangdong as a privileged analytical vantage point for understanding the multi-layered nature of colonialism in China between 1917 and 1927. The case reveals the coexistence of divergent imperial projects—metropolitan, corporate, and peripheral—and, simultaneously, competition among different visions of Chinese statehood. At the international level, the articulation of the Open-Door policy and the establishment of the New International Consortium reflect Western powers’ attempts to discipline monopolistic practices and to safeguard China’s territorial integrity under Beijing’s authority. This framework, however, clashes with the actions of Hong Kong–based British corporations (JM, B&S, HSBC), which, supported by local colonial authorities, pursued expansionist strategies in Guangdong aimed at securing privileged control over coal-mining districts in order to strengthen the colony’s political and economic position. At the same time, at the local level, the institutional instability generated by the conflicting coexistence of Beijing and Sun Yat-sen’s “Canton Republic” exposes the plurality of competing models of statehood. The Cantonese government sought to exploit European interest in mineral resources to accumulate material capital and diplomatic recognition, while the Guangdong federalist elites, represented by Chen Jiongming, opposed Sun’s centralizing and nationalist project. The Cassel affair thus emerges as a privileged lens through which to understand the interdependence between local, state, and global dynamics.