Since the late nineteenth century, China has introduced “Modern Law” from the West. What is the relationship between Traditional Chinese Law, Traditional Western Law, and Modern Law? The primary interest of this book is to clarify the differences between Traditional Chinese contractual society and the Modern contractual society that emerged from the Western legal Tradition. Hence, this chapter initially examines the distinctions and resemblances in three legal systems focusing on contracts. In traditional China, many social relations were constructed through mutual agreements. However, those agreements were grounded in human integrity, with the possibility of renegotiation in changing circumstances. On the contrary, traditional Western judicial authorities established a distinctive commitment format called “contract,” wherein agreement adherence was considered a fundamental principle despite changing conditions. However, the forms and scope of contractual services were limited in the pre-modern West. In the modern era, contractual services in the West evolved comprehensively, encompassing nearly all significant agreements individuals make. In other words, for the first time, the law becomes something like a platform on which almost all practical social relations can be built. This constitutes the essence of “Modern Law.” From this perspective, this chapter tries to characterize the history of law in the modern East and West as a history of conflict and accommodation between Modern Law and Indigenous Traditional Laws.