Suing for Only Part of Your Claim in Japan: When Can You Later Sue for the Remainder?

Japanese Attorney at Law - Bengoshi L.L.

• 9 min read

In civil litigation, plaintiffs often face strategic decisions about the scope of their claims. One such decision is whether to sue for the entirety of an alleged right or to initially pursue only a portion of it. This latter approach, known as an "partial claim" (ichibu seikyū), is permissible in Japanese civil procedure under certain conditions. However, the critical question that arises is: if a plaintiff litigates only part of a claim, can they subsequently file another lawsuit for the remaining portion (zanbu seikyū)? The answer in Japan is complex, hinging on how the initial claim was framed and the outcome of that first lawsuit, with the doctrine of res judicata (kihanryoku) and the principle of good faith (shingi-soku) playing pivotal roles.

The Concept and Permissibility of Partial Claims

A partial claim arises when a plaintiff, possessing a quantifiable and divisible claim against a defendant (e.g., a monetary debt, a series of quantifiable damages), chooses to seek judicial relief for only a specified part of that total claim in a lawsuit.

The right of a plaintiff to make such a partial claim is generally recognized in Japanese civil procedure. This stems from the fundamental principle of party disposition (shobunken shugi), enshrined in Article 246 of the Code of Civil Procedure (CCP), which grants parties, particularly the plaintiff, control over the initiation and scope of the matters to be adjudicated by the court. If a plaintiff is entitled to claim 10 million yen, they are generally free to limit their demand in a particular lawsuit to, say, 3 million yen.

Plaintiffs might opt for a partial claim strategy for various practical reasons:

  • Cost Management: In Japan, court filing fees are often calculated based on the monetary value of the claim (ad valorem). For very large but uncertain claims, a plaintiff might file a partial claim to reduce initial litigation costs while "testing the waters" with a smaller portion of the dispute (sometimes referred to as a "pilot lawsuit" or shiken soshō).
  • Risk Mitigation: In cases where the plaintiff anticipates defenses such as comparative negligence (which could reduce the recoverable amount) or a substantial set-off, they might strategically plead a partial amount to manage the potential impact of these defenses on the initially claimed sum.
  • Evidentiary Challenges: Sometimes, the full extent of a claim (especially certain types of damages) may not be easily quantifiable or provable at the outset of litigation. A plaintiff might sue for a known portion while continuing to gather evidence for the remainder.

The Core Issue: Res Judicata and Subsequent Claims for the Remainder

The primary legal challenge concerning remainder claims lies in the doctrine of res judicata. A final and binding judgment prevents the re-litigation of the same "subject matter of litigation" (soshōbutsu) between the same parties. If a judgment on a partial claim is deemed to have resolved the entire underlying claim for res judicata purposes, then a subsequent suit for any remaining part would be barred. Thus, the critical question is how the soshōbutsu is defined when only a part of a larger divisible claim is initially brought before the court.

Japanese case law has developed a crucial distinction based on how the plaintiff frames their initial partial claim.

1. The "Implied" or "Unclear" Partial Claim: Risk of Full Preclusion

If a plaintiff sues for a specific amount that is objectively only a part of a larger divisible right, but fails to clearly and expressly state in their pleadings that this is merely a partial claim and that they are reserving the right to sue for the remainder, Japanese courts generally treat the soshōbutsu as encompassing the entire underlying right, up to the amount actually pleaded.

This principle was established by the Supreme Court of Japan in its decision of June 7, 1957 (Minshu Vol. 11, No. 6, p. 948). The consequence of this approach is significant:

  • The judgment rendered in such a lawsuit (whether granting or denying the amount claimed) is considered to have res judicata effect over the entire underlying substantive claim.
  • Therefore, a subsequent lawsuit by the same plaintiff against the same defendant for any remaining portion of that same underlying claim will generally be dismissed as being barred by the res judicata of the first judgment.

The rationale is that, in the absence of a clear indication otherwise, the court and the defendant are entitled to assume that the plaintiff is seeking a definitive resolution of the entire matter up to the value stated, and the judgment is rendered on that basis.

2. The "Express Partial Claim" (Meiji no Ichibu Seikyū): Preserving the Right to Claim the Remainder

The situation changes significantly if the plaintiff, in the initial lawsuit, explicitly and clearly states that the amount claimed is only a specified part of a larger, identified divisible claim, and that they are expressly reserving the right to sue for the remaining portion at a later time.

In such cases of an "express partial claim," the Supreme Court of Japan, in its decision of August 10, 1962 (Minshu Vol. 16, No. 8, p. 1720), held that the soshōbutsu of the first lawsuit is limited only to the expressly claimed partial amount.

  • Consequently, the res judicata of the judgment in this first lawsuit attaches only to that specific partial claim.
  • This means that a subsequent lawsuit for the reserved remainder (zanbu seikyū) is generally not barred by res judicata and is, in principle, permissible.

The "express indication and reservation" serves as a crucial notice to both the court and the defendant. It clarifies that the plaintiff is not seeking a final determination of their entire potential claim in the initial proceeding but is limiting the scope of adjudication to the specified part. This allows the defendant to understand the limited nature of the initial suit and to adjust their litigation strategy accordingly, for example, by considering whether to file a counterclaim for a declaration of non-liability for the purported remainder.

Determining whether an initial claim constituted an "express partial claim" can sometimes be a contentious issue in the subsequent remainder suit. While an unambiguous statement in the original complaint is the clearest way to establish this, courts have, in some instances, found an implicit but sufficiently clear "express indication" based on the overall context of the pleadings, the nature of the claim (e.g., damages for ongoing or latent harm where the full extent was inherently unknowable at the time of the first suit), and the arguments presented. Legal commentaries suggest a trend towards a somewhat more lenient interpretation of what constitutes a sufficient indication, particularly in complex damages cases where quantifying the entirety of the loss upfront might be practically impossible for the plaintiff. For example, the Supreme Court on July 10, 2008 (Saibansho Jiho No. 1463, p. 4), allowed a subsequent claim for a different item of damage arising from the same tort, viewing the initial suit (which focused on other damage items) as implicitly involving a reservation for later-quantifiable damages.

The Good Faith Limitation: When an Express Partial Claim is Dismissed

The rules outlined above seemed to provide a relatively clear path: implied partial claims lead to full preclusion for the remainder, while express partial claims allow for subsequent remainder suits. However, a significant refinement to this framework was introduced by the Supreme Court concerning situations where an express partial claim is dismissed on its merits.

Consider this scenario: A plaintiff alleges a total divisible claim of 30 million yen. They file an express partial claim for 5 million yen, clearly reserving the right to sue for the remaining 25 million yen. However, after a full trial on the merits of the 5 million yen claim, the court dismisses it, finding, for example, that the entire underlying 30 million yen debt never existed or is otherwise unenforceable. Can the plaintiff then proceed to file a new lawsuit for the reserved 25 million yen remainder?

Under a purely formal application of the res judicata principles applicable to express partial claims, one might argue that since the soshōbutsu of the first suit was only the 5 million yen portion, the dismissal of that specific part does not create res judicata over the distinct (though related) 25 million yen remainder. This would suggest a remainder claim is still permissible.

However, the Supreme Court of Japan, in its landmark decision of June 12, 1998 (Minshu Vol. 52, No. 4, p. 1147), introduced a crucial limitation based on the principle of good faith and fair dealing (shingi-soku), which is a fundamental tenet of Japanese law, including civil procedure (CCP Article 2).

The Court ruled that if a plaintiff brings an express partial claim, and that claim is dismissed on the merits after a full examination of the facts and legal issues relevant to the entire underlying right (which is often necessary even to adjudicate a partial claim – e.g., to determine if any part of an alleged debt exists), then a subsequent lawsuit by the same plaintiff for the reserved remainder is, in the absence of special circumstances, considered contrary to the principle of good faith and is not permitted.

The rationale behind this important ruling includes:

  • Substantive Adjudication of the Whole: Even when adjudicating an express partial claim, the court frequently needs to delve into the existence, validity, and nature of the entire underlying claim to properly decide the fate of the portion being sued upon. If this comprehensive examination leads to a conclusion that the entire claim is unfounded, that substantive finding, while perhaps not formally res judicata over the unpleaded remainder, carries significant weight.
  • Preventing Abusive Re-litigation ("Mushikaeshi"): To allow a plaintiff whose partial claim was dismissed based on grounds that effectively negate the entire underlying right to then re-sue for the remainder would often amount to a "rehashing" (mushikaeshi) of the same core dispute. This would subject the defendant to the burden of re-litigating issues that were, for all practical purposes, decided in their favor in the first action.
  • Defendant's Reasonable Expectation of Finality: When a defendant successfully defends against a partial claim on grounds that go to the heart of the entire alleged liability, they develop a reasonable expectation that the matter is concluded. Allowing a remainder suit in such circumstances would undermine this expectation and the finality of the initial judgment.

The 1998 Supreme Court decision does allow for the possibility of a remainder claim if "special circumstances" exist. While not exhaustively defined, such circumstances would likely involve situations where:

  • The dismissal of the first partial claim was based on narrow, technical grounds specific only to that part, without a full merits determination of the entire underlying right.
  • New, critical, and previously unavailable evidence has emerged that fundamentally alters the basis of the claim for the remainder, and this evidence could not have been discovered or presented with due diligence in the first suit.
  • The nature of the claim itself involves elements that could only crystallize or become quantifiable after the first judgment (e.g., certain types of latent or progressively worsening damages, where the initial suit was understood to cover only what was known at the time, as seen in the Supreme Court's July 10, 2008 decision concerning different damage items).

Strategic Considerations for Litigants

The Japanese rules on partial and remainder claims necessitate careful strategic thinking:

For Plaintiffs:

  • Clarity in Pleading is Paramount: If intending to sue for only a part of a larger claim, it is absolutely crucial to expressly and unequivocally state in the complaint that (a) this is a partial claim, (b) the total amount of the underlying claim is X (if known), and (c) the right to sue for the remainder is specifically reserved. Ambiguity here can be fatal to a future remainder claim.
  • Assess the Risk of a Merits Dismissal: Be acutely aware that even with an express reservation, if your partial claim is dismissed on grounds that fundamentally undermine the entire alleged right, the 1998 Supreme Court good faith doctrine will likely bar a subsequent remainder claim. A partial claim strategy for a substantively weak case is therefore highly risky if the goal is to preserve the option of a second attempt.
  • Justify the Partial Claim Strategy: While permissible, be prepared that the court or the defendant might question the rationale for a partial claim if it appears to be purely for tactical maneuvering that could lead to inefficient serial litigation.

For Defendants:

  • Scrutinize the Plaintiff's Claim: When faced with what appears to be a partial claim, carefully analyze the plaintiff's pleadings to determine if it has been framed as an "express partial claim" with a reservation.
  • Consider a Counterclaim: If the plaintiff brings an express partial claim and the defendant believes they have no liability for the entire underlying claim (including the reserved remainder), the defendant might consider filing a counterclaim for a declaratory judgment confirming the non-existence of the entire debt or obligation. This could lead to a comprehensive resolution in the first lawsuit.
  • Invoke the Good Faith Principle: If an express partial claim was dismissed on merits that negate the entire underlying right, and the plaintiff subsequently files a remainder claim, the defendant should be prepared to argue that the new suit is barred by the principle of good faith, citing the Supreme Court's June 12, 1998 decision.

Conclusion

The ability to file a partial claim in Japan offers plaintiffs a degree of flexibility in managing litigation costs and risks. However, the subsequent permissibility of suing for the remainder of that claim is governed by a nuanced set of rules developed through key Supreme Court precedents. The critical factor is whether the initial suit was clearly and expressly designated as a partial claim with a reservation of rights for the remainder. Failure to make such an express indication typically results in the judgment on the pleaded amount having res judicata effect over the entire underlying claim, barring any subsequent suit for the rest.

Even when an initial claim is expressly partial, a plaintiff is not guaranteed the right to a second lawsuit for the remainder. If the express partial claim is dismissed on its merits after a full consideration of the underlying right, the principle of good faith, as articulated by the Supreme Court, will generally preclude a subsequent remainder claim that amounts to a mere re-litigation of the same fundamental issues. Litigants and their counsel must navigate this framework with careful pleading, a clear understanding of the subject matter of litigation, and an awareness of the significant implications of both res judicata and the overriding principle of good faith in Japanese civil procedure.