This study critically examines three recent competition law enforcement cases in Japan’s digital market to examine how competition law has been gradually refined during digitalization. Although each case pertains to important issues, this study focuses on extracting common competition law aspects by critically examining the following cases of Antimonopoly Law violations made by the Japan Fair Trade Commission: the e-commerce case against Amazon Japan, the shipping charges case against the Rakuten group, and billing-related violations by Apple. After extracting the common aspects from each case, this study aspects recursively re-examines the cases’ aspects to clarify the aspects that should be emphasized in competition law enforcement.