Defining the Battleground: How is the Scope of Comparison for Copyright Similarity Determined in Japanese Litigation?

In Japanese copyright infringement litigation, before a court can even begin to assess the substantive similarity between two works, a critical procedural step must occur: defining the precise "battleground" for comparison. This involves the plaintiff clearly specifying their copyrighted work and the defendant's allegedly infringing work, and often, the particular portions within those works that are claimed to be similar. How this scope is determined, and the extent to which parties can argue beyond the initially specified portions, are crucial aspects of the litigation process.

The Plaintiff's Fundamental Obligation: Identifying the Works at Issue

The onus is initially on the plaintiff, the party alleging copyright infringement, to clearly identify the works that form the basis of their claim. This is a fundamental requirement under Japan's Code of Civil Procedure (Article 133, Paragraph 2, Item (ii) and Rules of Civil Procedure, Article 53, Paragraph 1), which mandates that a complaint must specify the cause of action, including the necessary facts to identify the claim.

This means the plaintiff must unequivocally state:

1. Their Copyrighted Work (the "Infringed Work" - 被侵害著作物, hi-shingai chosakubutsu): The specific work in which they claim to hold copyright.
2. The Defendant's Allegedly Infringing Work/Use: The specific work or actions by the defendant that are alleged to infringe the plaintiff's copyright.

Failure to adequately specify these elements can lead to procedural challenges and difficulties in fairly adjudicating the claim.

Methods of Specification in Court Proceedings

The method by which these works are specified in Japanese court documents often depends on the nature of the works themselves:

• Visually Apprehensible Works (e.g., Photographs, Paintings, Single Illustrations): For works whose entire concrete expression can be readily grasped visually, it is common practice for the plaintiff to attach physical or digital copies (e.g., photographs, printouts) of both their work and the defendant's work to the complaint. These attachments are typically referred to as besshi (別紙), meaning an attached document or exhibit. In such cases, the content of these exhibits effectively defines the scope of the concrete expressions being put forth for comparison by the plaintiff.
• Lengthy or Primarily Non-Visual Works (e.g., Novels, Academic Texts, Screenplays, Musical Compositions, Films): When dealing with works where a quick visual inspection of the entirety is impractical or uninformative (like a long literary text or a film), a more detailed method of specification is required. This usually involves:
  1. Identifying the plaintiff's and defendant's overall works by objective identifiers such as title, author's name, publisher, date of publication/release, etc.
  2. Crucially, pinpointing the specific passages, sections, scenes, or elements within these larger works that are alleged to be similar. This is typically done using a detailed comparison table (別紙対比表 - besshi taihi-hyō). This table will juxtapose the relevant extracts from the plaintiff's work alongside the allegedly corresponding extracts from the defendant's work, allowing for a focused comparison of the specific points of contention.

Interpreting the "Infringed Work" When Comparison Tables Are Used

When a plaintiff uses a comparison table for lengthy works, the precise legal definition of the "infringed work" can sometimes be open to two interpretations, which can affect the subsequent scope of argument:

1. "Specific Portions as Independent Works" Interpretation: Each specific segment or portion identified and juxtaposed in the plaintiff's comparison table could be treated as if it were an independent copyrighted work (assuming each segment itself meets the criteria for copyrightability). The claim would then be that the defendant has infringed the copyright in each of these specific, identified portions.
2. "Entire Original Work as the Infringed Work" Interpretation: Alternatively, the "infringed work" may be understood as the plaintiff's entire original creation (e.g., the whole novel). In this scenario, the comparison table serves not to define multiple small copyrighted works, but rather to highlight specific instances or examples that demonstrate how the copyright in the larger, unified work has been infringed. The table, in this sense, forms part of the plaintiff's "method of attack" (kōgeki hōhō) in proving infringement of the broader work. This could mean infringement of the copyright in the entire work, or infringement of a part of the copyright existing in that entire work.

Generally, Japanese civil procedure affords the plaintiff considerable freedom in framing their claim. They can choose to define the "infringed work" broadly as the entire piece, or narrowly as a specific chapter, a single illustration, or even a distinct passage, provided that the chosen unit itself qualifies as a copyrighted work. The court's approach to the scope of comparison will often follow from how the plaintiff has structured this initial claim.

The Defendant's Scope: Arguing Beyond the Plaintiff's Initial Specifications

A critical question often arises: Is the defendant strictly confined to addressing only those portions of the works that the plaintiff has specifically highlighted as similar? Or can the defendant refer to other, unspecified parts of either the plaintiff's or their own work to argue against a finding of similarity?

• If the Plaintiff Claims Infringement of an Entire Work: When the plaintiff alleges that their entire work has been infringed (aligning with the "Entire Original Work" interpretation above), there is generally little procedural objection to the defendant pointing to substantial differences in other parts of the works. Such differences can be highly relevant to argue that, on balance, the works are not similar, or that the defendant's work is an independent creation, or that any shared elements are trivial in the context of the whole.
• If the Plaintiff Claims Infringement of Only Specific, Highlighted Portions: This scenario is more complex. If a plaintiff narrowly focuses on isolated, identical snippets, can a defendant bring in surrounding, differing material for context? The Intellectual Property High Court decision in the Fishing Game Town 2 case (August 8, 2012) offers significant guidance. The court indicated that even if a plaintiff specifies only certain parts for comparison, if those parts exist within what can be considered a "work with coherent unity" (まとまりのある著作物 - matomari no aru chosakubutsu), the defendant is generally permitted to argue that a consideration of other elements within that same coherent unit (even if not initially pinpointed by the plaintiff) would lead to the conclusion that the essential expressive features of the plaintiff's work are not, in fact, directly perceivable in the defendant's work.

The rationale is that a plaintiff should not be allowed to arbitrarily "cherry-pick" minute, decontextualized fragments of similarity if those fragments are embedded within a larger, unified expressive segment where surrounding differences might be crucial for a fair assessment. Allowing the defendant to refer to such immediate context within the same coherent unit is seen as necessary for a proper similarity evaluation and not necessarily an overreach beyond the "subject matter of litigation" (soshōbutsu).

The Concept of a "Work with Coherent Unity" (Matomari no aru Chosakubutsu)

This notion of a "work with coherent unity" is pivotal. It suggests that the "battleground" for comparison isn't always defined by the plaintiff's narrowest possible framing if that framing artificially isolates elements from their immediate, integral expressive context.
What constitutes a "coherent unit" is determined on a case-by-case basis, depending on the nature of the work.

• An individual illustration or photograph is typically a coherent unit.
• A chapter in a book, a single song in an album, or a specific, self-contained gameplay screen or sequence in a video game (as was argued in the Fishing Game Town 2 case) might also be considered such a unit.

The idea is to ensure that the similarity analysis is conducted at a meaningful level of expressive granularity, preventing distortions that might arise from an excessively fragmented or decontextualized comparison.

Procedural Limits: Subject Matter of Litigation and Principles of Argument

While the "coherent unity" concept allows for some flexibility, there are still procedural boundaries:

• Subject Matter of Litigation (soshōbutsu): Japanese civil procedure, largely adhering to the "old theory" of soshōbutsu, defines the subject matter by the specific legal right the plaintiff asserts (e.g., copyright in a particular, identified work or a defined part thereof). Arguments and evidence must generally remain relevant to this defined subject matter. A defendant usually cannot introduce entirely unrelated works or parts of works that have no bearing on the plaintiff's specific claim of infringement against a particular copyrighted unit.
• Principle of Party Disposition (shobunken-shugi): Outlined in Article 246 of the Code of Civil Procedure, this principle means that the plaintiff generally controls what claims are put before the court and the scope of the relief sought. The court is bound by the claims as presented by the parties.
• Principle of Adversarial Argument (benron-shugi) and Preventing "Trial by Ambush": This principle requires parties to clearly articulate the factual basis for their claims and defenses. While a defendant might be allowed to refer to immediately contextual elements within a "coherent unit" specified by the plaintiff, attempting to introduce extensive comparisons involving entirely distinct and unpleaded portions of very large works could be restricted. This is particularly so if it would unfairly surprise the plaintiff or require the court to adjudicate on matters not properly put into issue. The concrete expressions being compared are considered "evaluation-basis facts" (hyōka konkyo jijitsu) or "evaluation-hindrance facts" (hyōka shōgai jijitsu), and these generally need to be asserted by the parties.
  • It's important to note that if a plaintiff submits a visually apprehensible work (like a painting) in its entirety as an exhibit, all its constituent visual elements are generally considered to have been asserted.
  • However, for lengthy works where comparison tables are used to pinpoint similarities, the court's focus, and consequently the defendant's relevant scope for rebuttal, is primarily on those asserted elements and their immediate "coherent unit" context.

Specification Requirement: An Actually Created Unit of Expression

Finally, when a plaintiff specifies their "infringed work," it must generally correspond to a concrete unit of expression that they (or their predecessor-in-title) actually created. One cannot, for example, abstract a general "storyline" from a novel and claim copyright infringement based on similarity to that abstracted storyline alone, as the storyline itself, in its abstracted form, was not the specific work created and registered (if applicable) with its unique expressive details. Similarly, it's generally not permissible for a plaintiff to artificially construct an "infringed work" for litigation by combining non-contiguous snippets from their original piece. The basis of comparison should be the original work as created, either in its entirety or as a legitimately definable, continuous part thereof.

Conclusion: A Procedurally Defined Yet Context-Sensitive Battleground

In Japanese copyright litigation, the plaintiff bears the initial responsibility of clearly defining the copyrighted work and the allegedly infringing work, including the specific points of alleged similarity. While the defendant's response is primarily directed at these specified elements, the scope of permissible comparison is not always rigidly confined. The concept of a "work with coherent unity" allows for a degree of contextual analysis, enabling defendants to refer to immediately surrounding, differing elements if they are part of the same integral expressive unit highlighted by the plaintiff. This procedural framework, governed by the overarching principles of party disposition and adversarial argument, aims to ensure that the "battleground" for assessing copyright similarity is both clearly defined and allows for a fair, contextually informed evaluation of whether illicit copying of creative expression has occurred.