Can My Company Sue for Only a Portion of Our Claim in Japan to Test the Waters? The Risks and Nuances of "Partial Claims"

Japanese Attorney at Law - Bengoshi L.L.

• 8 min read

When faced with a substantial legal claim, companies often weigh the potential benefits of litigation against the considerable costs and risks involved. One strategy that might seem appealing is to initiate a lawsuit for only a part of the total claim – a "partial claim" (J.: ichibu seikyū – 一部請求) – perhaps to test the legal arguments, gauge the court's stance, or limit initial expenses. In Japanese civil procedure, while the concept of filing a partial claim is recognized, its implications for any subsequent attempt to claim the remainder are complex and fraught with nuances.

This article explores the permissibility of bringing partial claims in Japan, the critical distinction between "explicit" and "implicit" partial claims, how the outcome of the initial suit affects the right to pursue the remaining portion, and the interplay of procedural principles like res judicata and good faith.

The Starting Point: Party Disposition and the Plaintiff's Prerogative

Japanese civil procedure is fundamentally guided by the principle of party disposition (shobunken-shugi – 処分権主義). This principle grants litigants, particularly the plaintiff, significant control over the scope and subject matter of the lawsuit. It means that a plaintiff can generally decide how much of their total potential entitlement to sue for at a given time. Filing a claim for only a portion of what is allegedly owed or due is, therefore, generally permissible at the outset.

The motivations for such a strategy can be varied:

  • Cost Management: Court filing fees in Japan are calculated based on the monetary value of the claim. By initially claiming a smaller amount, a plaintiff can reduce these upfront costs.
  • "Test Litigation" (Shiken Soshō – 試験訴訟): A party might file a partial claim to obtain a judicial determination on key legal or factual issues common to the entire claim before committing the resources necessary for a full-scale legal battle. This can be particularly relevant in novel or complex cases.
  • Strategic Considerations: There might be other tactical reasons, such as simplifying the initial phase of the dispute or focusing on the most easily provable part of a claim.

However, while initiating a partial claim is generally allowed, the crucial question arises later: can the plaintiff subsequently file another lawsuit to recover the remaining portion (zambu seikyū – 残部請求) of the original, larger claim? The answer is not straightforward and hinges significantly on how the initial partial claim was framed and adjudicated.

The Decisive Factor: Explicit vs. Implicit Partial Claims

The cornerstone of the Japanese legal approach to subsequent remainder claims is the distinction between an "explicit partial claim" (meiji no ichibu seikyū – 明示の一部請求) and an "implicit" one.

Explicit Partial Claims: Keeping the Door Open (Usually)

If a plaintiff, in their initial lawsuit, clearly and explicitly states that the amount being claimed is only a part of a larger, identifiable entitlement and that they are reserving the right to sue for the remainder later, Japanese case law generally permits a subsequent lawsuit for that remainder. The Supreme Court of Japan, in a judgment dated August 10, 1962, established that in such cases, the subject matter of litigation (soshōbutsu – 訴訟物) in the first suit is considered to be only the explicitly claimed portion. Consequently, the res judicata (claim preclusion) effect of the judgment in the first suit does not extend to the unclaimed remainder, leaving the plaintiff free to pursue it in a separate action.

One rationale supporting this is that if the defendant is made aware that the first suit is only for a part of a larger claim, they have the opportunity to seek a broader resolution in that same proceeding, for instance, by filing a counterclaim for a declaration that no further amount (i.e., the remainder) is owed. Thus, a subsequent suit for the remainder is not considered an unfair surprise to a defendant who was on notice.

Implicit Partial Claims: A More Restricted Path

If the plaintiff sues for an amount that is less than their total potential entitlement but fails to explicitly state that it is a partial claim or to reserve their rights to the remainder, the situation is different. Such a claim is often treated as if the plaintiff is seeking the entirety of what they believe they are entitled to under the legal and factual theory presented in that specific lawsuit. A subsequent attempt to claim an additional amount arising from the same underlying incident or transaction could be barred by res judicata if the court deems the initial claim to have encompassed the entire dispute as framed by the plaintiff at that time.

A Supreme Court judgment of June 7, 1957, illustrates this. The plaintiff had initially sued for what amounted to a divisible portion of a debt without asserting that the underlying debt was a joint one (which would have entitled the plaintiff to the full amount from any single debtor). Having obtained judgment for only the divisible part, the plaintiff later tried to sue for the remainder by arguing the original suit was merely a partial claim of a larger joint debt. The court did not permit this subsequent action, effectively treating the first suit as defining the scope of the claim then made.

The Impact of the First Judgment's Outcome

The permissibility of a remainder suit is not solely dependent on the explicitness of the initial partial claim; the outcome of that first suit is also critical.

  • If the Explicit Partial Claim is Successful: As noted, a subsequent suit for the remainder is generally allowed.
  • If the Explicit Partial Claim is Dismissed on the Merits: This scenario introduces significant complexity. The Supreme Court judgment of June 12, 1998, provides crucial guidance. It held that even if the first suit was an explicit partial claim, if that claim was dismissed on its merits, and if, in the course of dismissing it, the court conducted a full deliberation and made findings regarding the entirety of the underlying right or debt (concluding, for example, that the entire alleged debt did not exist or was invalid), then a subsequent suit for the remainder is not permitted.

The reasoning here is subtle. The bar to the second suit is not strictly based on the res judicata of the first judgment covering the remainder (since the soshōbutsu was formally only the partial amount). Instead, allowing the plaintiff to re-litigate the remainder, after the entire underlying basis of the claim was effectively debunked in the first suit, is considered an abuse of process and a violation of the principle of good faith and fair dealing (shingi soku – 信義誠実の原則) owed to the defendant. The defendant, having successfully defended against the substance of the entire alleged right in the first proceeding, has a legitimate expectation not to be vexed again for the same matter.

The practical challenge lies in determining whether the court in the first instance genuinely conducted a "full deliberation on the entire claim." This often requires a careful analysis of the pleadings, evidence, and the reasoning in the first judgment. Simply because a partial claim was dismissed does not automatically mean the entire underlying claim was fully adjudicated.

The Japanese approach to partial claims involves several fine points:

  • Clarity of "Explicitness": To preserve the option of a remainder suit, the plaintiff must be unequivocally clear in their initial pleadings that they are claiming only a portion and reserving the right to claim more. Ambiguity can be fatal to a subsequent claim.
  • Defendant's Counter-Strategies: A defendant faced with an explicit partial claim should consider strategic responses. As mentioned, one option is to file a counterclaim seeking a declaration that the plaintiff is not entitled to the alleged remaining portion of the claim, thereby aiming for a comprehensive resolution in the initial proceedings.
  • Later-Manifesting Damages: A special situation arises with damages that were genuinely unknown and unforeseeable at the time of the first lawsuit (e.g., latent injuries from an accident that only manifest years later). In a judgment on July 18, 1967, the Supreme Court allowed a subsequent suit for such later-discovered damages, reasoning that these constituted a different subject matter (soshōbutsu) from the damages claimed in the first suit, even if the first suit hadn't been explicitly framed as partial concerning these specific future, unforeseen damages. This indicates a pragmatic approach by the courts when true unforeseeability is established.
  • Theoretical Underpinnings: There is ongoing academic discussion in Japan about the precise theoretical basis for these rules – whether it is a pure application of soshōbutsu theory, an extension of res judicata to the reasoning of the prior judgment in certain cases, or an application of the broader principle of good faith (shingi soku). Regardless of the exact theory, the overarching goal is to strike a balance between the plaintiff's autonomy in framing their claim, the defendant's right to finality, and the efficient administration of justice.

Procedural Issues Concerning Remainder Claims

  • No Separate Suit for Remainder While First Suit is Pending: If a plaintiff has initiated an explicit partial claim, they generally cannot file a separate, new lawsuit for the remainder while the first suit is still pending. Doing so would likely be considered a prohibited duplicate litigation under CCP Article 142. The proper procedural route is to file a motion to amend the claim (uttae no henkō – 訴えの変更) in the existing lawsuit to include the full amount (CCP Article 143).
  • Statute of Limitations (Prescription): Crucially, filing a partial claim generally only interrupts (tolls) the statute of limitations (J.: jiko – 時効) for the portion actually claimed. The plaintiff must remain vigilant about the limitation period for any unclaimed remainder, as it continues to run.
  • Partial Claims and Set-Offs: The interaction with set-off defenses can also be complex. In a notable decision on June 30, 1998, the Supreme Court permitted the remainder of an explicitly identified partial claim (where the first suit regarding that partial claim was still pending) to be used by that same party as a set-off defense in a different, separate lawsuit against them. This suggests that using the remainder for a defensive set-off in another case might not always be viewed as constituting prohibited duplicate litigation in the same way as filing an affirmative new suit for that remainder would.

A Brief Comparison with U.S. "Claim Splitting" Rules

For U.S. legal professionals, the Japanese approach to partial claims may evoke parallels with, and differences from, the doctrine of res judicata (specifically claim preclusion) and the rule against "splitting a cause of action" in American jurisprudence.

In the U.S., claim preclusion generally bars a party from re-litigating the same claim that was, or could have been, litigated in a prior action between the same parties or their privies that concluded in a final judgment on the merits. This often means that a plaintiff must assert all grounds for relief arising from a single "cause of action" or "transaction or occurrence" in one lawsuit. Failing to do so can preclude a subsequent suit for omitted parts of that claim.

While the underlying policy goals—finality and judicial economy—are similar, the analytical frameworks differ. The Japanese system's strong emphasis on the soshōbutsu theory and the distinction between "explicit" and "implicit" partial claims, coupled with the application of the shingi soku principle in certain contexts, presents a distinct approach compared to the often broader transactional test used in U.S. claim preclusion analysis. Exceptions to claim splitting in the U.S. (e.g., consent by the defendant, court order, or statutory authorization) also have their own criteria.

Strategic Considerations for Businesses

The decision to file a partial claim in Japan is a strategic one that requires careful thought:

  • Weighing Pros and Cons: The potential benefits of reduced initial costs or obtaining a "test" ruling must be weighed against the significant risk of being barred from claiming the remainder, or at least facing complex procedural hurdles and arguments of bad faith.
  • The Imperative of Explicit Reservation: If a partial claim strategy is pursued, it is absolutely critical to make the partial nature of the claim and the reservation of rights to the remainder unequivocally clear in the initial pleadings. Any ambiguity could be detrimental.
  • Anticipating Defendant's Moves: A defendant, upon receiving an explicit partial claim, might strategically use a counterclaim for a declaration of non-liability for the entire alleged sum, thereby forcing a broader adjudication.
  • Consultation with Local Counsel: Given the complexities and the nuances of Japanese case law, obtaining advice from experienced Japanese legal counsel is indispensable before embarking on a partial claim strategy. Counsel can advise on the appropriate phrasing, assess the risks, and help navigate the procedural requirements.

Conclusion

Filing a partial claim in the Japanese civil justice system is a permissible but strategically delicate maneuver. While it can offer advantages in terms of initial cost savings and testing the viability of a larger claim, the pathway to subsequently recovering any remaining portion is narrow and subject to strict conditions. The critical distinction between explicitly reserving the right to claim the remainder and failing to do so can determine the fate of any subsequent action.

Furthermore, even an explicit partial claim does not guarantee a green light for a later suit for the remainder if the initial litigation involved a comprehensive adjudication that effectively negated the entirety of the underlying right. In such cases, the principle of good faith (shingi soku) can act as a bar. Businesses contemplating this approach must proceed with caution, ensuring utmost clarity in their initial pleadings and a full understanding of the evolving jurisprudence that balances a plaintiff's right to frame their action with the need for procedural fairness and the finality of judgments.