This book provides a comprehensive exploration of Japan's competition policy, integrating the latest research on antitrust enforcement and economic theory. It combines legal and economic perspectives to examine key regulatory approaches in Japan and beyond. Structured into four main sections--fundamental theories, digital economy, public procurement, and future challenges--each chapter not only delves into cutting-edge research but also offers introductory discussions to guide readers through complex topics. The book is designed for scholars, legal practitioners, policymakers, and tech strategists who seek to understand the current landscape of Japanese competition law and its global implications.