This study compares three case studies in the context of Japanese competition law enforcement with the US experience. Although each case involves important issues, this study focuses on extracting common aspects of competition law by critically examining the following cases of Antimonopoly-Law-suspected violations pursued by the Japan Fair Trade Commission (JFTC): the e-commerce case against Amazon Japan, the shipping charges case against the Rakuten group, and billing-related suspected violations by Apple. After extracting the common aspects from each case, this study recursively re-examines the cases to clarify the aspects that should be emphasized in competition law enforcement.