What are the Unwritten Rules for Preparing Japanese Court Documents?

Japanese Attorney at Law - Bengoshi L.L.

01 Jun 2025 • 12 min read

Navigating litigation in any foreign jurisdiction presents unique challenges, and Japan is no exception. Beyond the codified laws and procedural rules, a set of "unwritten rules" and expectations often dictates the effectiveness of court submissions. For legal professionals accustomed to different systems, understanding these nuances is crucial for presenting a compelling case. This article delves into the practical aspects of preparing court documents for Japanese civil litigation, emphasizing formatting, style, structure, and the all-important judicial perspective.

The Foundation: Formatting and Presentation (書式・体裁 — Shoshiki & Teisai)

While Japanese law does not impose a rigid, statutory format for most court documents, courts provide reference formats that are widely adopted and signal a level of professional diligence. Adherence to these, or at least an understanding of their underlying principles, is a foundational step.

Official (Yet Flexible) Guidelines:
The prevailing standard, often referenced by court materials such as those from the Tokyo District Court and the Japan Federation of Bar Associations (日本弁護士連合会 - Nihon Bengoshi Rengōkai, or Nichibenren), typically involves:

Paper Size and Orientation: A4 size paper, used in landscape (横書き - yokogaki) orientation.
Layout: Approximately 37 characters per line and 26 lines per page. Recommended margins are generally 30mm on the left and 35mm at the top.
Font: A 12-point font is standard for the main text. Mincho (明朝) typeface is the norm, with Gothic (ゴシック) often used for headings and subheadings to provide visual distinction. Headings themselves can be in a larger font size as appropriate.
Pagination: For documents exceeding one page, page numbers should be placed at the bottom center of each page.

A recent trend, possibly driven by a desire to reduce paper volume or faxing costs, has seen some practitioners fitting more text onto a single page by using smaller fonts or tighter line spacing. However, this can be counterproductive, as such documents may be difficult for judges, particularly those with more years on the bench, and opposing counsel to read comfortably. Prioritizing readability is generally the wiser course.

Visual Aids: Diagrams, Tables, and Judicial Perception (図表・別紙・別表 — Zuhyō, Besshi, Beppyō)
The use of diagrams, attached sheets, and tables has become more common, aided by advancements in document creation technology. These can be invaluable for clarifying complex factual chronologies, intricate relationships between parties (e.g., family trees in inheritance disputes), or defining numerous specialized terms in technical cases.

However, their use should be strategic and supplemental. Judges generally welcome visual aids that genuinely enhance understanding, especially given that they primarily grasp case details through written submissions. Diagrams can visualize points that are cumbersome to explain in text alone, and tables can bring clarity to numerous or complex elements like timelines, disputed issues, or damage calculations.

There are caveats:

Supplement, Not Substitute: Formal assertions and arguments must always be articulated in the main body of the written submission; visual aids are there to support and illustrate.
Clarity is Key: Overly detailed or convoluted tables can negate their purpose by sacrificing scannability. Detailed arguments belong in the brief itself, with the table offering a concise summary.
Admissibility and Contention: Opposing parties may find it challenging to make specific admissions or denials regarding the content of complex diagrams or tables, which can sometimes blur the focus on core disputed points.
Court-Endorsed Formats: In certain specialized litigation areas, such as construction defect cases (e.g., "defect lists" - 瑕疵一覧表, kashi ichiranhyō) or traffic accident compensation claims (e.g., "case summaries" or "damage calculation tables" - 損害額一覧表, songaigaku ichiranhyō), some courts, like the Tokyo District Court, may even recommend or provide templates for such tables.

Emphasis Techniques: Use with Discretion (太字・下線等 — Futoji, Kasen tō)
Highlighting key phrases or easily misunderstood points using bold text, gothic font, underlining, or emphasis marks (傍点 - bōten) is relatively common. However, moderation is essential. Overuse dilutes the impact, rendering the technique meaningless. Furthermore, if the emphasized points are not genuinely critical or are misplaced, it can reflect poorly on the filer's judgment.

The use of colored text or digital highlighting in the main body of a brief is generally discouraged and can be perceived as excessive. Practical issues also arise, as court photocopiers are often black and white, and fax transmissions may not preserve such formatting, hindering the creation of clear file copies for the court or opposing counsel.

That said, using bold or gothic font for headings or for terms being formally defined (e.g., "Hereinafter referred to as the 'Agreement'") is an accepted practice, even seen in court judgments. Similarly, when quoting excerpts from evidence within a brief, underlining crucial passages (often accompanied by a note like 「下線部は引用者による」 - "underline added by citer") is common and helpful. When submitting copies of academic articles or other literature as evidence, marking the sections directly relied upon in the argument with an underline or a subtle marker is also standard practice.

Footnotes: Utility and Judicial Skepticism (脚注 — Kyakuchū)
Footnotes can be used for information that, while relevant, is not central to the core line of argument and might disrupt the flow of the main text if included directly (e.g., lengthy parenthetical asides). Some practitioners argue that footnotes should be strictly limited to citing academic literature or case precedents.

Regardless of preference, it's safer to assume that material relegated to a footnote may not be considered a formally asserted point by the court or opposing counsel, and therefore might not form part of the basis for the judgment. Judges tend to view footnoted information as something the author implicitly acknowledges as less critical than the main text. While not a frequent feature in Japanese legal briefs, they can serve a purpose for readability if used judiciously.

The Core: Language, Style, and Structure (文体・文章表現・構成 — Buntai, Bunshō Hyōgen, Kōsei)

The substance of a legal argument is conveyed through its language and structure. Japanese legal writing places a high premium on clarity, precision, and a professional tone.

Clarity and Conciseness: The "One Idea Per Sentence" Rule (簡潔性・明確性 — Kanketsusei, Meikakusei)
The fundamental principle is to be concise and easily understood (簡潔にわかりやすく - kanketsu ni wakariyasuku). This typically involves:

Short Sentences: Keeping sentences as short as practicable.
Subject-Verb Proximity: Ensuring subjects and their corresponding verbs are not widely separated.
Appropriate Conjunctions: Using conjunctions logically to connect ideas.
One Idea Per Sentence: A common guideline is 「一文一義」 (ichibun ichigi) – one sentence, one meaning. This aids significantly in clear communication.
Avoiding Ambiguity: Factual assertions should be phrased to eliminate, as much as possible, any room for misinterpretation.
Consistent Terminology: Using the same terms to describe the same concepts or entities throughout the document is crucial to avoid confusion.

While lawyers in the past, drafting by hand, tended towards shorter sentences, the advent of word processors has sometimes led to longer, more complex sentence structures. While a lengthy sentence can be perfectly clear if logically constructed (as some court judgments demonstrate), it is generally safer to opt for brevity unless one is confident in maintaining impeccable logical coherence over extended phrasing.

Maintaining a Professional Legal Standard (法律文書としての水準 — Hōritsu Bunsho to shite no Suijun)
While brevity is valued, an overly colloquial or staccato style, with too many very short sentences, can be difficult to read and may not meet the expected professional standard. Court documents are addressed to legal professionals—judges and opposing counsel—who expect a certain level of formality and precision. Vague or poorly phrased assertions may invite requests for clarification (釈明 - shakumei) from the court or make it difficult for the opposing party to formulate a proper response.

Logical Structure: Headings and Organization (論理的構成 — Ronriteki Kōsei)
A well-structured document greatly aids comprehension.

Headings and Subheadings (見出し・小見出し - Midashi, Komidashi): These should be used appropriately to break down the argument into logical sections. Judges find it helpful when titles and subheadings clearly indicate the argument or point being made in the subsequent section, allowing them to anticipate the content and better follow the logical structure. For example, a specific heading like "The Defendant Did Not Owe the Duty of Care Asserted by the Plaintiff" is more informative than a general one like "Regarding Breach of Contract." However, excessively long headings can be counterproductive.
Paragraphing: Avoid "walls of text." Proper paragraphing, with each paragraph typically focusing on a distinct point, is essential for readability.
Itemization (項目立て - Kōmokudate): When itemizing points or facts, a hierarchical structure similar to that used in judgments is often preferred (e.g., 第1 → 1 → (1) → ア → (ア) → a → (a)), with appropriate indentation at each level. Word processing outlining features can be very helpful for maintaining this structure automatically.
Table of Contents and Summaries (目次・要旨 - Mokuji, Yōshi): For substantial documents (a general guideline might be 20 pages or more), including a table of contents at the beginning, and sometimes a summary of the main arguments, can be extremely beneficial for the reader.

The Perils of Overly Long Documents:
Judges and practitioners alike acknowledge that the ease of computer-based drafting has sometimes led to excessively long submissions. While there's no magic number, a preparatory brief exceeding 20 pages, for instance, might be viewed with caution by a judge, prompting them to wonder if it could have been more focused. Even the judiciary internally considers excessively long judgments problematic; for example, a judgment in a case handled by a single judge that exceeds 15 pages might be seen as needing justification. This underscores the preference for focused, succinct argumentation. One common reason for lengthy documents is a lack of time for refinement; drafting often involves developing the logical structure as one writes, and the fear of omitting a crucial point can lead to including more than is strictly necessary.

The Judicial Gaze: How Japanese Judges Evaluate Submissions (裁判官はこう見る — Saibankan wa Kō Miru)

Understanding how judges approach and process court filings is perhaps the most critical "unwritten rule." Japanese judges, like their counterparts elsewhere, operate under significant time constraints and caseload pressures.

Early Impression Formation: The Primacy of Initial Filings:
A crucial point to grasp is that Japanese judges often begin forming their impressions of a case at a very early stage, sometimes as soon as the complaint (訴状 - sojō) is submitted. They actively analyze the initial pleadings to understand the core issues and identify what further deliberation or evidence will be necessary. Waiting until all arguments are exhausted before forming a view would hinder effective case management and issue-spotting. Consequently, the more diligent a judge, the earlier they are likely to begin this process of impression formation. Once an initial impression solidifies, it can be challenging to overturn. This makes the clarity, persuasiveness, and thoroughness of the initial documents—the complaint, the first answer—particularly vital.

The "One-Glance Understanding" Principle in Light of Judicial Workload:
Judges in major urban centers like Tokyo may handle several hundred civil cases concurrently (a sole-judge civil caseload can range from 150 to 250 active cases). They might preside over more than ten hearings in a single day, often leaving substantive reading of documents for the evening. In such an environment, a document that can be understood "at a glance" (一読して理解できる書面 - ichidoku shite rikai dekiru shomen) or upon a single, focused reading, is highly valued. Efforts to enhance clarity through formatting and structure are generally well-received, though excessive or distracting embellishments should be avoided.

Rhythm and Flow: Facilitating Judicial Review (リズムよく読める書面 - Rizumu Yoku Yomeru Shomen)
When forming their views, judges read submissions while concurrently referring to the cited evidence. An effective document allows this process to occur smoothly, enabling the judge to assess facts ("this seems provable," "this too is likely true") with a certain rhythm. If a judge has to pause frequently to search for the relevant part of an exhibit because citations are unclear or imprecise, their train of thought is disrupted, and the persuasive flow of the argument is lost.

Substantiating Your Case: Assertions and Citations (事実主張・証拠の引用・法的主張 — Jijitsu Shuchō, Shōko no In'yō, Hōteki Shuchō)

Clear assertions backed by precise citations are the backbone of any persuasive legal document in Japan.

Factual Assertions and Evidence Citation (事実主張・証拠の引用 - Jijitsu Shuchō, Shōko no In'yō):
For every factual assertion made, its basis should be evident.

Direct Evidence: If direct evidence exists, it must be clearly cited. Exhibit numbers should generally be assigned and cited sequentially as they first appear in the submissions.
Inferential Reasoning: If a fact is to be inferred from indirect facts, the submission should lay out these indirect facts, the evidence supporting them, and, where necessary, the experiential rules (経験則 - keiken soku) that bridge the gap to the inferred conclusion.
Normative Requirements: When asserting matters involving normative evaluation, such as negligence (過失 - kashitsu) or just cause (正当事由 - seitō jiyū), the specific facts supporting that evaluation must be explicitly pleaded.
The Importance of Citation: Judges frequently encounter assertions where the evidentiary basis is unclear. Reading a document without knowing if the stated facts are supported by evidence creates doubt and hinders persuasion. The Rules of Civil Procedure (specifically, Article 79, Paragraph 4 of the Regulations for Civil Procedure - 民事訴訟規則第79条第4項) mandate that for each fact requiring proof, the supporting evidence must be indicated. It is the attorney's responsibility to meticulously guide the judge, showing which evidence supports which factual claim.
Precision in Citation: Vague citations are unhelpful. If citing a contract, the specific article or clause should be identified unless its relevance is self-evident from the context. For voluminous exhibits, such as lengthy reports or medical records, precise page numbers (e.g., "Exhibit Ko-3, p. 5") or even specific sections within a page (e.g., "Exhibit Ko-3, p. 5, paragraph 2, concerning X") should be provided. While marking or highlighting photocopies of evidence (such as literature or newly printed web pages) is acceptable to draw attention to key parts, original contemporaneous documents should generally be submitted without alteration by counsel. If counsel does add markings to a copy, this should be explicitly noted.

Asserting Experiential Rules (経験則の主張 - Keikensoku no Shuchō):
Experiential rules—propositions about common human behavior or natural phenomena—play a significant role in judicial reasoning, particularly in bridging indirect evidence to factual conclusions.

General vs. Specialized Rules: Generally accepted experiential rules (e.g., simple laws of physics, matters of common societal understanding) typically do not require formal proof. However, specialized experiential rules, such as complex medical or scientific principles, or specific industry customs and trade practices (業界の取引慣行 - gyōkai no torihiki kankō), do require proof.
Clarity and Certainty: Even for general experiential rules, their degree of certainty can vary. Counsel should be mindful of the specific content and the established reliability of any experiential rule they rely on and articulate it clearly for the judge.
Evidentiary Support for Specialized Rules: When asserting a specialized experiential rule, supporting evidence must be cited. For industry customs, this might involve publications from industry bodies, articles in reputable trade journals (though the credibility of such sources varies), or even references to how such customs have been recognized in prior similar court decisions. Relying solely on witness testimony for specialized customs can be risky.

Making Legal Arguments and Stating Opinions (法的主張・意見 - Hōteki Shuchō, Iken):

Logical Consistency: Legal arguments must, above all, be logically consistent.
Accurate Citations: Precision in citing statutes, case precedents, and academic literature is paramount. This includes specifying the exact article and paragraph of a statute, the full case citation (court, date, and reporter volume/page, e.g., 民集 - Minshū for Supreme Court civil cases), and for academic works, the author/editor, title, edition, and specific page numbers.
Supporting Opinions: Even when stating an opinion on matters of fairness or appropriateness rather than strict legal interpretation, the basis for that opinion should be articulated.

Professional Conduct in Writing (品位・誤記・過激表現 — Hin'i, Goki, Kageki Hyōgen)

The tone and professionalism of court submissions can significantly influence their reception.

Maintaining Dignity and Avoiding Excessive Acrimony (品位の保持 - Hin'i no Hoji):
Slanderous remarks about the opposing party or overly aggressive and attacking language are generally counterproductive. Such tactics rarely sway a judge and may instead be perceived as an attempt to compensate for a weak argument with strong rhetoric. While robustly pointing out contradictions in an opponent's claims is part of advocacy, excessive nitpicking or "gotcha" tactics over trivial matters can be tiresome and ineffective. The focus should remain on the substantive issues.

Handling Errors: Corrections and Responses (誤記への対応 - Goki e no Taiō):
Minor typographical errors can usually be corrected orally during a hearing, but the standard and preferred practice is to submit a written correction, often styled as a "Motion to Correct Pleading" (e.g., 「訴状訂正の申立書」 - sojō teisei no mōshitatesho for a complaint). This ensures clarity in the record. Particularly for corrections to the core factual allegations in a complaint, which might be directly incorporated into the judgment, courts often instruct parties to submit a clean, corrected version as an attachment.

When the opposing party makes a minor error, a degree of magnanimity is generally appropriate. Seizing on trivial mistakes rarely advances one's own case, unless the "error" is in fact an attempt by the opponent to subtly alter their factual position. Deliberately basing arguments on an obvious clerical error by the opponent is viewed as unconstructive.

The Line Not to Cross: Disciplinary Actions for Extreme Expressions (過激表現と懲戒 - Kageki Hyōgen to Chōkai):
The PDF from which this article draws information mentions instances where attorneys have faced disciplinary action for using inflammatory or deeply offensive language in their written submissions. This serves as a stark reminder that while advocacy can be zealous, it must remain within the bounds of professional decorum. Examples include derogatory statements about an opponent's character or the use of highly offensive analogies.

Key Takeaways for International Practitioners

For legal professionals engaging with the Japanese court system, several "unwritten rules" stand out:

Judicial Perspective is Paramount: Japanese judges begin forming impressions early, value clarity and conciseness due to heavy workloads, and expect meticulous support for all factual assertions.
Formality and Readability Matter: While not rigidly prescriptive, adherence to common formatting standards (A4 landscape, clear fonts, logical structure) demonstrates professionalism and aids comprehension.
Precision in Language and Citation: Ambiguity is disfavored. Consistent terminology and precise, readily verifiable citations for facts, experiential rules, and legal authorities are crucial.
The "Supporting Role" of Visuals and Footnotes: Diagrams and tables should clarify, not complicate. Footnotes are generally for peripheral information or citations and may not be considered part of the core argument.
Professional Tone: Undignified or overly aggressive language is counterproductive. Focus on reasoned argument rather than ad hominem attacks or excessive nitpicking.

Understanding these underlying principles and expectations can significantly enhance the effectiveness of written submissions in Japanese courts, paving the way for more persuasive advocacy.