In spite of the common global position of protecting the right to confidential communication, the Japanese prison authorities create barriers to communication between pre-trial inmates and defence counsel. Any correspondence, including correspondence between pre-trial inmates and defence counsel, may be opened and read by prison staff. In addition, prison authorities have established regulations to prohibit any visitors from bringing in cameras or mobile phones. They do not allow counsel to take photos in visiting rooms, claiming that these regulations are equally applicable to lawyers. This article examines the legality of the current practice regarding mail censorship and the prohibition of photography in visiting rooms, taking into consideration international human rights standards. It concludes that the current practice diverges from the international human rights standards including the Nelson Mandela Rules, which protects the full confidentiality of communication between inmates and lawyers, and access to effective legal aid. Since the arrest of Nissan’s former chairman Carlos Ghosn in November 2018, Japan’s ‘hostage justice’ system – in which suspects are held for a long period in harsh conditions to coerce a confession – has encountered a barrage of criticism. It should be noted, however, that interruption of inmates-defence counsel communication constitutes another dark side of Japanese criminal justice. This article will shed light on the everyday issues which Japanese defence counsel face in actual criminal cases.