Chapter 1 examines the evolving concept of lawfare and contrasts it with the principle of lawfulness in international law. It traces the historical and theoretical foundations of war and law, from Grotius and Clausewitz to contemporary debates on hybrid and cognitive warfare. Various scholarly perspectives on lawfare are explored, highlighting its manifestations across international and domestic domains, including the reinterpretation of legal norms, the use of international tribunals, and national legislation. Drawing on case studies, the chapter illustrates how lawfare has become a central instrument in modern conflicts. Against this backdrop, the book advances the concept of lawfulness as a counter-strategy, emphasizing transparency, public opinion, and adherence to international law—the “3P formula.” This approach underscores the distinction between lawful implementation of law and unlawful legal actions, arguing that only the latter constitutes lawfare. Ultimately, the chapter situates lawfare and lawfulness within the specific framework of the South China Sea disputes, providing a factual foundation for understanding the legal confrontations that will be further explored in the following chapters of the book.