Class Actions and Collective Litigation in Japan

Introduction

Japan does not have a full-fledged US-style class action system in which a representative party litigates on behalf of an absent class, binding all members unless they opt out. Instead, Japanese law has developed a patchwork of collective litigation mechanisms that serve analogous functions in specific domains: consumer protection, securities regulation, environmental torts, and labour law. The most significant recent development is the Act on Special Measures for Collective Litigation for Damages Caused by Unfair Practices (2013, effective 2016), which introduced a Japanese opt-in class action for consumer damages.

The Consumer Organisation Litigation

The Consumer Contract Act (Shōhisha Keiyaku Hō, 2000) first introduced a form of collective litigation by empowering qualified consumer organisations (tokutei shōhisha dantai) to seek injunctions against unfair contract terms and misleading advertising. This system, known as shōhisha dantai soshō (consumer organisation litigation), does not permit the recovery of damages. Its function is purely preventive: a qualified consumer organisation may apply to the court for an order restraining a business operator from using an unfair contract term or engaging in a misleading representation.

The Japan Consumer Organisation (Shōhisha Chōsa Kikō) and other certified entities have brought dozens of injunction actions, achieving significant results in areas such as mobile-phone subscription contracts, gym membership terms, and online marketplace conditions. The system is modelled on the German Unterlassungsklage and the French action en cessation.

The 2016 Collective Damages System

The Act on Special Measures for Collective Litigation for Damages Caused by Unfair Practices (Act No. 80 of 2013, effective 1 October 2016) introduced Japan’s first collective damages mechanism. It applies only to two categories of claims: (1) damages arising from violations of the Consumer Contract Act (unfair contract terms and misleading representations), and (2) damages arising from violations of the Act on the Prohibition of Unfair Premiums and Misleading Representations (Fusei Keihin-rui oyobi Fusei Hyōji Bōshi Hō).

The Two-Stage Procedure

The collective litigation proceeds in two stages:

Stage One — Determination of Common Issues. A Specified Qualified Consumer Organisation (tokutei shōhisha dantai) — an organisation certified by the Prime Minister — brings an action seeking a declaration that a business operator is obliged to compensate consumers who have suffered loss because of an unfair practice. The court determines the common issues of liability: whether the practice was unfair, whether it caused loss, and the basic method of calculating damages.

Stage Two — Individual Quantification of Damages. Following a favourable Stage One judgment, individual consumers must opt in to the proceedings within a court-set period. They file individual claims for the quantification of their specific damages. The court may adopt simplified procedures to resolve these individual claims efficiently, including the use of prescribed damage schedules.

Opt-In, Not Opt-Out

The system is strictly opt-in. No consumer is bound by the Stage One judgment unless they affirmatively opt in during Stage Two. This feature has been criticised for limiting the system’s effectiveness: in practice, only a small fraction of affected consumers typically opt in, and the administrative burden of managing the opt-in process is substantial.

Practical Impact

As of 2026, approximately ten collective damages actions have been brought under the 2016 Act. The cases have involved defective health supplements, misrepresented financial products, and unfair cancellation fees in service contracts. The amounts recovered have been modest by US standards. The system remains in its infancy, and commentators have called for amendments to expand its scope and to introduce an opt-out mechanism for low-value claims.

Securities Litigation

Shareholder Derivative Actions (kabunushi daihyō soshō) are the most active form of representative litigation in Japan. Article 847 of the Companies Act permits any shareholder who has held shares for at least six months to sue a director (or former director) on behalf of the company for breach of duty. The derivative action has been used extensively since the 1990s, following the introduction of reduced court filing fees.

The leading case is Tokyo Nissan Chemi Soshō (1994), in which shareholders recovered substantial damages from directors who had approved a negligent business strategy. Since then, derivative actions have targeted directors’ decisions in mergers, investments, and compliance failures. The number of derivative actions filed annually in the Tokyo District Court exceeds 100.

Securities Fraud Class Actions. Japan does not have a specific securities class action mechanism. Individual investors may sue for damages under Article 21-2 of the Financial Instruments and Exchange Act (Kinyū Shōhin Torihiki Hō), which imposes liability on issuers for false statements in securities reports. Multiple investors may join their claims under the rules on joint actions (kyōdō soshō), but there is no representative mechanism that binds non-parties.

Environmental Mass Torts

Japan has a significant tradition of mass tort litigation in the environmental field. The Minamata (1956–1973), Itai-itai (1960s–1970s), Niigata Minamata (1965–1970s), and Yokkaichi Asthma (1960s) cases — collectively known as the “Four Big Pollution Trials” (yon dai kōgai soshō) — were landmark proceedings in which hundreds of plaintiffs jointly sued industrial polluters. These cases employed the joint action mechanism under Articles 40–41 of the Code of Civil Procedure, which allows multiple plaintiffs to sue together if their claims arise from the same factual or legal basis.

The environmental mass torts established important precedents on causation (the “epidemiological” approach adopted in Yokkaichi) and on the joint and several liability of multiple defendants. They also catalysed the enactment of the Pollution-Related Health Damage Compensation Act (Kōgai Kenkō Higai Hoshō Hō).

Multiple Party Litigation

The Code of Civil Procedure provides several mechanisms for the aggregation of multiple claims:

Joint Actions (kyōdō soshō, Articles 40–41 CCP). Multiple plaintiffs may sue jointly if their rights or obligations arise from the same factual or legal basis. Each plaintiff is a separate party, and the judgment is independent as to each.

Common Issue Joinder (renreki, Article 39 CCP). Where separate actions raise common questions of law or fact, the court may order that they be consolidated for trial. The consolidation does not create a single proceeding but allows for the simultaneous hearing of evidence.

Test Case Litigation. In practice, Japanese courts and parties sometimes agree on a test case strategy: one or a small number of representative actions are litigated to judgment, and the parties then settle the remaining cases in accordance with the test case’s outcome. This has been common in large-scale product liability and pharmaceuticals cases.

Evaluation and Reform Proposals

Japanese collective litigation has been characterised as “fragmented” and “incomplete.” The absence of an opt-out mechanism, the restriction of the collective damages system to consumer claims, and the modest scale of recoveries have led to calls for reform. The Japan Federation of Bar Associations (Nichibenren) has proposed the introduction of a general opt-out class action for civil damages. The Ministry of Justice established a study group in 2024 to consider expanding the scope of the 2016 Act and introducing an opt-out mechanism for low-value dispersed-loss claims.

The comparative literature suggests that Japan’s cautious approach reflects a concern to avoid the perceived excesses of US-style class action litigation. The Japanese system prioritises the preservation of party autonomy and the avoidance of the “blackmail” settlement dynamic. Whether the balance is optimal remains an open question.