Understanding the Japanese Prosecutor ("Kensatsukan"): What Are Their Unique Roles, Responsibilities, and Ethical Standards?

Japanese Attorney at Law - Bengoshi L.L.

• 7 min read

In Japan's criminal justice system, the prosecutor, or kensatsukan (検察官), holds a position of immense power and profound responsibility. Their role extends far beyond simply presenting cases in court; they are deeply involved in investigations, possess broad discretion over whether to indict, and are guided by a distinct ethical framework aimed at achieving substantive justice. For those interacting with or observing the Japanese legal system, understanding the multifaceted nature of the kensatsukan—their historical development, diverse duties, and the ethical ideals that shape their conduct—is crucial.

A Unique Blend: Historical Development and Current Structure

The modern Japanese prosecutorial system is a product of historical evolution, drawing influences from continental European traditions and undergoing significant reforms after World War II, with some American legal concepts being introduced.

  • Historical Roots: Pre-WWII, the Japanese system was heavily influenced first by French and then German models. Prosecutors, like judges, were often seen as part of a unified judicial-bureaucratic structure under the Ministry of Justice, tasked with objectively ascertaining the truth. This period saw prosecutors wielding considerable investigative authority.
  • Post-WWII Reforms: The post-war Constitution and accompanying legal reforms aimed to democratize the justice system and establish clearer separations of power. The Public Prosecutor's Office Act (検察庁法, Kensatsuchō Hō) established prosecutors' offices as distinct administrative organs, organizationally separate from the courts. Democratic oversight mechanisms, such as Prosecution Review Commissions (検察審査会, Kensatsu Shinsakai), were introduced, allowing citizen panels to review decisions not to prosecute.
  • Current Structure and Independence: Despite these reforms, the Japanese prosecutor retains a unique character. They are career public officials who generally exercise their powers with a significant degree of independence. The Prosecutor's Office Act (Article 25) provides them with strong status guarantees, protecting them from undue political or external pressure in their decision-making. While the Minister of Justice has a general supervisory role, their power to direct the Prosecutor-General on specific cases (Prosecutor's Office Act, Art. 14) is extremely limited and has been historically fraught with political controversy when exercised.
  • The Prosecutor-Unity Principle (Kensatsukan Dōittai no Gensoku, 検察官同一体の原則): Japanese prosecutors operate within a hierarchical structure, with the Prosecutor-General at the apex. This principle means that all prosecutors effectively act as a single, unified body. Superiors (Chief Prosecutors, etc.) have the authority to direct and transfer cases among subordinate prosecutors. This is operationalized through the kessai seido (決裁制度), an internal system requiring prosecutors to obtain approval from superiors for critical decisions like indictments, non-prosecutions, and appeals. This system aims to ensure nationwide consistency, fairness, and a multi-layered review of prosecutorial judgments, rather than simply imposing top-down commands.

Core Duties and Responsibilities of the Japanese Prosecutor

The Public Prosecutor's Office Act (Article 4) outlines the prosecutor's primary functions:

  1. Investigation: Prosecutors have the authority to investigate any type of crime. While police typically conduct initial investigations, prosecutors can direct police investigations (Criminal Procedure Code, Art. 193), conduct their own supplementary investigations, and directly handle complex cases such as major white-collar crimes, corruption, and tax evasion. They play a crucial role in ensuring the legality and adequacy of police work.
  2. Institution of Public Prosecution (Kōso, 公訴): This is the prosecutor's exclusive power to decide whether or not to formally charge a suspect and bring them to trial.
    • Discretionary Prosecution (Kiso Benigi Shugi, 起訴便宜主義): A defining feature of the Japanese system is the principle of discretionary prosecution (Criminal Procedure Code, Art. 248). Even if there is sufficient evidence to secure a conviction, a prosecutor can choose not to indict based on various factors. These include the offender's character, age, and circumstances; the gravity of the offense; and circumstances after the offense, such as remorse, restitution to the victim, or the likelihood of rehabilitation without formal punishment. This broad discretion results in a significant number of cases being diverted from formal trial through non-prosecution (often "suspension of prosecution" - kiso yūyo, 起訴猶予).
    • High Conviction Rate Context: The practice of indicting only when prosecutors believe there is a very high probability of conviction based on strong, legally obtained evidence contributes to Japan's famously high conviction rate. This is linked to their perceived duty to pursue substantive truth and avoid unnecessary trials of those unlikely to be convicted.
  3. Requesting Just Application of Law: In court, prosecutors present the state's case, examine witnesses, and make arguments regarding the facts and the appropriate application of the law, including sentencing recommendations.
  4. Supervising Execution of Judgments: After a conviction and sentence, prosecutors oversee the proper execution of penalties.
  5. Broader Roles as "Representative of the Public Interest": Beyond criminal matters, Japanese prosecutors have various functions stipulated in other laws. They may act as state attorneys in significant civil litigation involving the government (shōmu kenji, 訟務検事), participate in certain family law proceedings, or engage in international legal cooperation and law-making efforts within the Ministry of Justice. A more recent focus is on "entry support" (iriguchi shien, 入口支援) for offenders, aiming to connect individuals released at the prosecution stage (e.g., via suspended prosecution) with welfare and rehabilitation services to prevent recidivism.

Ethical Standards: The "Prosecutor's Ideals" (Kensatsu no Rinen)

Following a series of high-profile prosecutorial misconduct cases and wrongful convictions in the 2000s (such as the Ashikaga and Muraki cases, the latter involving evidence tampering by a prosecutor), which severely damaged public trust, the Supreme Public Prosecutor's Office formulated and published the "Prosecutor's Ideals" (検察の理念, Kensatsu no Rinen) on September 30, 2011. This document serves as the fundamental ethical compass for all Japanese prosecutors, clarifying their mission, role, and basic stance in performing their duties. It aims to rebuild trust and ensure the proper exercise of prosecutorial power.

The "Prosecutor's Ideals" emphasizes several core tenets:

  1. Public Servants Committed to Justice: Prosecutors are to act as servants of the entire populace, for the public interest, strictly observing laws, and performing duties with fairness, impartiality, and sincerity. (Ideals, Point 1; Introduction)
  2. Respect for Fundamental Human Rights and Due Process: They must respect human rights, ensure the proper conduct of criminal proceedings, and fully understand the roles of judges and defense counsel. (Ideals, Point 2)
  3. Unyielding Pursuit of Substantive Truth: The ultimate goal is to "clarify the true facts of the case to ensure that the innocent are not punished and that the truly guilty do not escape punishment." They must diligently seek the truth, overcoming any difficulties without easy compromise. (Ideals, Point 3; Introduction)
  4. Objective and Multifaceted Evidence Evaluation: Prosecutors must strive to collect and grasp sufficient evidence, both inculpatory and exculpatory ("positive and negative evidence"), and evaluate it coolly and from multiple perspectives, without preconceived notions. (Ideals, Point 4) This implicitly includes a duty to consider and, where appropriate, disclose evidence favorable to the accused.
  5. Proper Interrogation Practices: When questioning suspects or witnesses, prosecutors must ensure the voluntariness of statements and give necessary consideration to the interviewee, striving to obtain truthful statements. (Ideals, Point 5)
  6. Consideration for Victims: They must listen to the voices of crime victims and their families and respect their legitimate rights and interests. (Ideals, Point 6)
  7. Proper Management of Information and Confidentiality: Evidence and information must be managed appropriately to avoid unjustly harming the reputation of those involved or obstructing investigations or trials. Secrecy must be strictly maintained. (Ideals, Point 7)
  8. Cooperation for Broader Criminal Policy Objectives: Prosecutors should collaborate with police, correctional institutions, probation offices, and other relevant agencies to contribute to crime prevention and offender rehabilitation. (Ideals, Point 8)
  9. Continuous Self-Improvement: They must constantly endeavor to acquire and improve legal knowledge and skills, as well as cultivate broad learning to respond to diverse and changing societal phenomena. (Ideals, Point 9)
  10. Humility, Reflection, and Organizational Culture: Prosecutors should maintain an attitude of humility, constantly reflecting on whether their exercise of authority truly serves the public interest and avoiding self-aggrandizement or succumbing to undue pressure. They should learn from experience and contribute to a vibrant organizational culture that allows for free and vigorous discussion and mutual support. (Ideals, Point 10; Introduction)

A key theme running through the "Prosecutor's Ideals" is that the aim is not simply to secure convictions at all costs. Rather, it is to achieve an "appropriate disposition and appropriate sentencing that aligns with the common sense of the people, based on the true facts of the case." (Ideals, Introduction). This involves a commitment to fairness even towards the suspect/defendant.

The "Prosecutor's Ideals" directly address many of the ethical challenges inherent in the prosecutorial role:

  • Avoiding Tunnel Vision and Prosecutorial Bias: The strong emphasis on objective evidence evaluation, including the duty to consider evidence unfavorable to the prosecution's initial theory, is designed to counteract confirmation bias.
  • Relationship with Defense Counsel: While the Japanese criminal justice system is adversarial, the Ideals call for prosecutors to understand and respect the role of defense counsel. This includes refraining from improper tactics to weaken the defense and an implicit, if not always fully realized in practice, obligation regarding the disclosure of exculpatory evidence.
  • Internal Accountability and Decision-Making: The kessai seido (internal approval system) provides a mechanism for multiple levels of review, intended to ensure that decisions are well-reasoned and consistent. The Ideals also promote a culture of open internal discussion and learning from mistakes.

Comparison with U.S. Prosecutorial Ethics

While both Japanese and U.S. prosecutors are tasked with pursuing justice, their roles, powers, and the ethical frameworks guiding them have notable differences:

  • Discretion: Both systems grant prosecutors significant discretion. However, Japan's principle of discretionary prosecution (kiso benigi shugi) is exceptionally broad, allowing non-prosecution even in cases with strong evidence, based on a wide range of offender and offense characteristics.
  • Duty to Disclose Exculpatory Evidence: In the U.S., this duty is constitutionally mandated (Brady v. Maryland). In Japan, it is strongly implied by the "Prosecutor's Ideals" (objective collection of all evidence) and has been a focus of reform discussions, particularly regarding the scope and timing of disclosure.
  • Investigative Role: Japanese prosecutors generally have more extensive direct investigative powers and formal supervisory authority over police investigations than many of their U.S. counterparts (especially federal prosecutors, who typically rely on agencies like the FBI for investigations).
  • Political Accountability: Many U.S. prosecutors (e.g., state District Attorneys) are elected officials and thus more directly politically accountable. Japanese prosecutors are career civil servants within a national, hierarchical organization, with democratic control exercised more indirectly through mechanisms like Prosecution Review Commissions.

Conclusion

The Japanese kensatsukan operates within a unique and complex system, wielding considerable power over the lives of individuals and the course of justice. Their role is shaped by a history that blends continental European traditions with post-war reforms, and by an ongoing societal expectation that they act not just as accusers, but as objective representatives of the public interest dedicated to uncovering substantive truth. The "Prosecutor's Ideals," born out of a period of introspection and a desire to rebuild public trust, provide a vital ethical compass. These ideals call for a prosecutor who is not only legally skilled and diligent but also fair-minded, respectful of human rights, humble, and unwavering in their pursuit of justice that aligns with the common sense of the people. For businesses and individuals interacting with this system, understanding this ethical framework is key to comprehending the motivations and standards that guide these powerful legal figures.