Res Judicata in Japan (Kihanryoku) - Part 1: What is its True Nature and How Does it Function in Subsequent Litigation?
The principle of res judicata, known in Japanese as Kihanryoku (既判力), is a fundamental concept in civil procedure globally, and Japan is no exception. It refers to the binding effect of a final and unappealable judgment, ensuring that once a matter has been definitively adjudicated, it cannot be re-litigated between the same parties. This doctrine is crucial for legal stability, judicial economy, and the finality of disputes. However, the precise theoretical underpinnings of Kihanryoku and the specific ways it operates can be complex. This article, the first of a two-part series, will delve into the essential nature of Kihanryoku as understood in Japanese legal theory and explore the core scenarios in which its preclusive effects come into play in subsequent litigation.
The Essence of Kihanryoku: Unpacking the Theories (既判力の本質論 - Kihanryoku no Honshitsuron)
At its heart, Kihanryoku means that once a judgment becomes formally binding (acquires 形式的確定力 - keishiki-teki kakuteiryoku, meaning it can no longer be appealed through ordinary means), its substantive determination gains a special authority. The prevailing definition in Japan describes Kihanryoku as the substantive binding force of this final judgment: its content dictates the legal relationship between the parties, preventing them from making assertions contrary to the judgment, and barring courts in subsequent proceedings from rendering contradictory rulings on the same matter. But why does a judgment wield such power? Several theories attempt to explain this.
A. The Substantive Law Theory (実体法説 - Jittaihōsetsu)
An earlier, historically significant theory was the Substantive Law Theory. This view posited that a final judgment directly alters the underlying substantive legal rights and relationships themselves to conform to the judgment's content. In essence, the judgment was seen as creating a new substantive reality, even if the original judgment was, from an objective standpoint, erroneous. Subsequent courts would then simply observe and apply this judicially created substantive state.
However, this theory faced significant criticisms and is now largely discarded in Japan:
- It problematically implied that even an objectively incorrect judgment becomes "correct" by reshaping substantive reality, effectively eliminating the notion of a misjudgment.
- It struggled to reconcile with the principle of the relative effect of judgments (相対効の原則 - sōtaikō no gensoku), as codified in Article 115, Paragraph 1, Item (i) of the Code of Civil Procedure (CCP). This principle states that Kihanryoku generally only binds the parties to the litigation (and certain successors). If a judgment between A and B regarding an absolute right (like ownership, which is effective erga omnes) substantively altered that right, it would unjustly affect third parties (e.g., the true owner C, who was not part of the A-B litigation).
- It could not adequately explain the Kihanryoku effect of procedural judgments (訴訟判決 - soshō hanketsu), such as a dismissal of an action for lack of a procedural requirement (e.g., Supreme Court, July 16, 2010, Minshu Vol. 64, No. 5, p. 1450). Such judgments do not rule on substantive rights, so there is no substantive reality for them to alter.
B. The Procedural Law Theory (訴訟法説 - Soshōhōsetsu)
The dominant understanding of Kihanryoku in Japan today is rooted in the Procedural Law Theory. This theory maintains that the binding effect of a final judgment is purely procedural. It does not change the underlying substantive legal state itself (unless the judgment is a formative one with a specific formative effect, or keiseiryoku - 形成力, or is subsequently enforced). Instead, Kihanryoku dictates how the prior judicial determination must be treated within the procedural context of any subsequent litigation between the same parties (or those in privity) concerning the same subject matter. The prior judgment establishes a binding procedural benchmark. This explains why legal texts might describe the outcome of Kihanryoku as creating a situation similar to the substantive right having been disposed of, rather than stating that the right is substantively altered by Kihanryoku alone.
Within the Procedural Law Theory, two main variations explain how this procedural binding occurs:
- The Binding Force Theory (拘束力説 - Kōsokuryokusetsu): This is the prevailing view in Japanese legal scholarship and practice. It holds that the subsequent court is procedurally bound by the specific determination (the adjudicated conclusion) contained in the prior final judgment regarding the litigated subject matter.
- Positive Effect: The subsequent court must accept the prior determination as conclusive and use it as a premise for its own decision-making if that determination is relevant.
- Negative Effect: As a consequence, parties are precluded from making factual or legal assertions in the subsequent litigation that contradict the matter determined by the prior judgment. Any such contradictory assertions are to be disregarded by the court.
It's important to note that under this theory, a subsequent action is not automatically dismissed as inadmissible merely because it touches upon a matter to which Kihanryoku applies (unless, for example, it lacks a separate "interest to sue"). The action can proceed, but the court’s adjudicative process concerning the previously decided issue is constrained by the Kihanryoku of the prior judgment. However, the court can still consider new facts or legal arguments that have arisen after the standard time (kijunji - 基準時) of the prior judgment. The kijunji is typically the moment of the conclusion of oral arguments in the fact-finding instance (usually the first or second instance court) that rendered the final, binding decision on that factual predicate.
- The Non Bis In Idem Theory (一事不再理説 - Ichiji-fusairisetsu): This theory, which holds significant sway in some other civil law systems like Germany, views Kihanryoku as establishing a negative procedural bar. A subsequent action concerning the same subject matter that has already been definitively adjudicated is deemed inadmissible (futekihō - 不適法). Consequently, such an action must be dismissed by the court through a procedural judgment (soshō hanketsu - 訴訟判決), without re-examination of the merits.
While a minority view in Japan, it offers a different conceptual lens. Its lesser acceptance in Japan stems partly from perceived difficulties in its application to situations involving preliminary questions (senketsu kankei - 先決関係 – where the prior adjudicated matter is a prerequisite for the current claim) and its potentially more rigid stance concerning the kijunji, as it tends to only recognize the finality of the first judgment without allowing for a new substantive judgment (and thus an updated kijunji) in the second suit if new circumstances arise. The Binding Force Theory, by allowing the second suit to proceed to a new substantive judgment (albeit one bound by the prior determination on the old facts), can more flexibly accommodate changes occurring after the first judgment's kijunji.
(A brief note on "Reflex Effect" / Hanshakō (反射効): The Procedural Law Theory, unlike the Substantive Law Theory, requires a distinct explanation for situations where a judgment between parties A and B might legally affect a third party C due to C's special substantive legal relationship with A or B (e.g., a surety's obligation depending on the principal debtor's adjudicated debt). This "reflex effect" is seen as a substantive law consequence, separate from the procedural Kihanryoku, though its existence and scope are subjects of ongoing debate, with Japanese case law generally being restrictive towards recognizing it broadly.)
The Scope of Kihanryoku's Operation: When Does It Apply?
Article 114, Paragraph 1 of the CCP dictates that Kihanryoku attaches to the determination contained in the main text of the judgment (主文中の判断 - shubun-chū no handan) concerning the subject matter of litigation (soshōbutsu - 訴訟物). It generally does not extend to the reasoning, findings of fact, or opinions expressed by the court in the body of the judgment, unless specifically provided for by law (a key exception being findings on a set-off defense, per Article 114, Paragraph 2).
This preclusive effect, aimed at preventing "re-litigation" (mushikaeshi - 蒸し返し), is primarily recognized in three types of relationships between the subject matter of the prior action and that of the subsequent action:
A. Identity Relationship (Dōitsu Kankei - 同一関係)
This is the most straightforward application of Kihanryoku. It occurs when:
- The subject matter of litigation (soshōbutsu) in the prior action and the subsequent action are identical.
- Even if the formal soshōbutsu (e.g., a claim for negative declaration versus a claim for performance) differs slightly, the underlying "right-relationship" (kenri kankei - 権利関係) being adjudicated is essentially the same. For example, if Party A sues Party B for performance of a contractual obligation and the claim is dismissed with finality, Party B cannot then sue Party A for a declaration that the same contractual obligation does not exist (or vice versa, if Party B first obtained a declaration of non-existence, Party A cannot then sue for performance based on the same alleged facts predating the kijunji).
An important practical note: If a plaintiff wins a judgment for performance (e.g., an order for payment), they generally cannot sue again for the same performance. This is usually not because Kihanryoku bars the second claim itself, but because the plaintiff lacks a new "interest to sue" (uttae no rieki - 訴えの利益). They already possess an enforceable title (債務名義 - saimu meigi) from the first judgment. Exceptions are rare but might include situations where the original judgment document is lost, or a new lawsuit is the only viable way to interrupt the statute of limitations for the judgment debt itself.
B. Preliminary Question Relationship (Senketsu Kankei - 先決関係)
This relationship arises when the subject matter that was conclusively determined in the prior action (soshōbutsu of the first suit) constitutes a necessary preliminary question (a logical prerequisite) for the determination of the subject matter in the subsequent action.
- Example: A prior final judgment confirms A's ownership of a specific piece of land in a dispute between A and B. If A subsequently sues B for eviction from that same land, and A's right to evict is predicated on that ownership, the prior determination of A's ownership (which was the soshōbutsu of the first action and thus has Kihanryoku) will be binding in the eviction suit. The court in the eviction suit cannot re-determine the ownership issue contrary to the first judgment for the period up to its kijunji.
It is crucial to distinguish this from the reverse situation: Kihanryoku does not attach to findings on issues that were merely preliminary within the reasoning of the prior action but were not its actual soshōbutsu. For instance, if the prior action was for eviction based on an alleged lease agreement, and in the reasons for judgment the court found that the lease agreement was valid, this finding on the lease's validity does not, by itself, have Kihanryoku. If a party wishes to obtain a binding determination on such a preliminary issue within the first suit, they might need to file an interlocutory declaratory action (chūkan kakunin no uttae - 中間確認の訴え) under Article 145 CCP, thereby making that issue a soshōbutsu itself.
C. Contradictory Relationship (Mujun Kankei - 矛盾関係)
This is arguably the most complex scenario. It occurs when the subject matter determined in the prior action and the subject matter of the subsequent action are, from a substantive law perspective, logically contradictory or mutually exclusive. The two claims cannot co-exist.
- Example: A prior final judgment in a suit by B against C confirms B's ownership of a specific movable property. If C subsequently sues B, asserting that C is (and was at the time of the prior judgment's kijunji) the owner of that same property, C's claim is in a contradictory relationship with the prior determination of B's ownership.
- Basis of Preclusion: The preclusive effect in such cases is often understood as being "mediated by substantive law principles." A common example is the principle of "one object, one right" (ichibutsu ikken shugi - 一物一権主義) in property law, which dictates that only one ownership right can exist for a single object at any given time. Kihanryoku operates procedurally between the parties, utilizing the logic of these substantive principles. So, if B's ownership is established with Kihanryoku against C, then C cannot, in a subsequent suit against B, validly claim ownership of the same item for the same period.
- Nuance in Prevailing Interpretation: There has been a traditional tendency in Japanese doctrine to recognize this contradictory relationship preclusion most clearly when the prior judgment affirmed the right of the plaintiff in the first action (e.g., B's ownership was confirmed). If, in the first action, B's claim for ownership was dismissed (meaning the judgment established, with Kihanryoku, that "B is not the owner" as against C), the prevailing view has sometimes been more hesitant to automatically bar C's subsequent claim for C's own ownership solely on the basis of a mujun kankei flowing from B's loss. The argument is that "B is not owner" does not logically necessitate "C is owner." However, this can lead to complexities, as B might then attempt to re-assert their dismissed ownership claim as a defense against C's suit. More contemporary analyses tend to argue that Kihanryoku's negative effect should indeed prevent B from making assertions in the second suit that are flatly contradictory to the res judicata of the first judgment (i.e., B cannot argue they were the owner at the prior kijunji).
Conclusion (Part 1)
Kihanryoku is a vital doctrine ensuring the finality and consistency of judicial decisions in Japan. Its essential nature is best understood through the Procedural Law Theory, specifically the Binding Force Theory (Kōsokuryokusetsu), which explains its operation as a procedural constraint on subsequent litigation rather than an alteration of substantive rights. The preclusive effect of Kihanryoku, attaching to the determination in the main text of a final judgment, primarily functions in subsequent actions involving relationships of identity, preliminary questions, or logical contradiction with the previously adjudicated subject matter. Understanding these foundational principles is the first step to grasping the full implications of res judicata in the Japanese legal system. Part 2 of this series will explore further nuances, including the crucial distinction between Kihanryoku "arising" versus "extending," and how courts address issues that fall outside the direct preclusive scope of a prior judgment.