A disconnection has historically existed between international and domestic justice. In China, international justice and domestic justice were long treated as two autonomous yet interconnected systems, akin to the concept of Yin and Yang. With the establishment of the International Criminal Court (ICC) in 2002, the two systems began to increasingly work in tandem. The principle of complementarity is one of the cornerstones of the ICC's architecture, according to which states have primary jurisdiction over the ICC. So long as the legal system of a state can efficiently investigate and prosecute the core international crimes prohibited in the Rome Statute, the ICC will not intervene. However, if a state is unwilling or unable to investigate and prosecute these crimes, the ICC will invoke the principle of complementarity to step in.