A standalone confidentiality clause inside the main contract covers most ordinary commercial relationships in Japan, because the clause only needs to protect information already shared under a signed agreement. A separate Non-Disclosure Agreement (秘密保持契約, NDA) is the better structure when information has to be protected before the main contract exists, such as during due diligence or term negotiation, or when the protection needs to outlive the main contract by years rather than months.
Does Japanese Law Already Protect Confidential Information Without a Clause?#
No single statute gives a Japanese contracting party an automatic, specific duty to keep the other side's information confidential. The Civil Code (民法) imposes a general good-faith duty (信義則) on every contracting relationship, but that duty is broad and fact-dependent, built for resolving disputes after the fact rather than stopping a leak before it happens. A party that disclosed a customer list, a pricing model, or a technical drawing with no confidentiality language in the contract and no separate NDA is relying on a court's after-the-fact reading of good faith, not on a right it can point to in writing.
That gap is also why confidentiality does not appear on the Must-Include side of Aplash's standard Japan contract clause checklist alongside items like anti-social forces exclusion or governing law. It sits in the case-dependent category: whether a clause is needed at all, and whether a clause is enough or a separate NDA is required, depends on the information and the stage of the relationship, not on a market convention the way the anti-social forces representation does.
When Does a Confidentiality Clause Inside the Main Contract Cover You?#
A confidentiality clause folded into the main contract is enough when the information only needs protecting for the life of that contract, between the same two parties, starting from the contract's own effective date. A distribution agreement, a services agreement, or a supply contract where both sides exchange pricing, specifications, and customer data as part of performing the deal typically fits this pattern. The clause defines what counts as confidential, the permitted uses, the carve-outs (information already public, independently developed, or required to be disclosed by law), and a survival period that runs past termination.
The clause works because the obligation and the underlying deal are the same instrument. If the contract terminates for breach, or expires at the end of its term, the confidentiality obligation survives only as long as the survival clause says it does, typically a fixed period of one to several years. A single ongoing commercial relationship with no separate pre-contract phase and no outside party needing the same protection gets no extra legal protection from adding a dedicated NDA on top; it only adds a second document to track and reconcile against the main contract's terms.
When Do You Need a Separate NDA Instead?#
A separate NDA fits three situations: before the main contract exists, when more parties need coverage than the eventual contract will have, and when the confidentiality term needs to run longer or on different conditions than the main contract itself. Due diligence and term-sheet negotiation are the clearest case. Information changes hands before either party has committed to anything, so there is no main contract yet to carry a confidentiality clause, and the Civil Code's general good-faith duty does not stand in for an explicit obligation during that exposed period.
Multi-party and longer-horizon cases follow the same logic. A joint development discussion involving a counterparty, its parent company, and a subcontractor needs one NDA naming all of them, because a confidentiality clause buried inside a bilateral main contract cannot bind a party who never signs that contract. Licensing and technology-sharing relationships, where the disclosed material (source code, formulas, manufacturing processes) needs protection for years after the commercial relationship ends, also call for a standalone NDA with its own survival term, decoupled from whatever term the eventual supply or services contract carries.
Japan M&A NDA and LOI structuring covers a related but different question, where the NDA sits inside a deal-specific sequence toward a Letter of Intent and a definitive agreement. The ordinary-commercial-contract NDA discussed here has no deal path behind it; it protects information during negotiation or an ongoing relationship on its own terms.
How Does Japan's Trade Secret Law Interact With the Contract?#
A confidentiality clause or NDA and statutory trade secret protection are two different layers, and the contract layer is what makes the statutory layer usable. The Unfair Competition Prevention Act (不正競争防止法), Article 2, Paragraph 6, defines a protected trade secret (営業秘密) as information meeting three requirements at once: it must be managed as secret (秘密管理性), it must have commercial usefulness (有用性), and it must not be publicly known (非公知性). Information that fails any one of the three gets no statutory remedy against misuse, however sensitive it is.
The secrecy-management requirement is where a well-drafted confidentiality clause or NDA does real work. The Ministry of Economy, Trade and Industry (経済産業省, METI) has published guidelines on trade secret management describing the kind of access controls, marking, and contractual restriction that count toward managing information as secret; a contract clause that defines confidential information, restricts its use, and limits who inside the counterparty's organization can see it is part of the evidence a court looks for on that first requirement. A party with sensitive technical or commercial information and no contractual confidentiality language is weaker on the secrecy-management point even where the information would otherwise qualify.
Check an assignment-of-receivables restriction and a liability cap or liquidated damages clause in the same review pass: confidentiality breaches are exactly the kind of claim a liability cap can quietly limit when the cap language carries no carve-out for confidentiality and IP breaches.
Drafting either structure, these are the points worth deciding on purpose instead of leaving to a template default.
(a) Define "Confidential Information" by category (technical, commercial, personal data) rather than a blanket "all information disclosed," so the scope is provable later. (b) Set a survival period for the obligation that outlasts the main contract term; a confidentiality duty that expires with the contract defeats its own purpose. (c) Carve out information already public, independently developed, or disclosed under legal compulsion, since a clause without carve-outs is harder to enforce as written. (d) Confirm whether personal data is involved; if so, align the clause with the Act on the Protection of Personal Information (個人情報保護法) specifically, since its consent and cross-border transfer rules go beyond an ordinary confidentiality obligation. (e) Decide and state who bears the burden if information needs disclosure to a subcontractor, affiliate, or regulator, before the issue comes up mid-contract.
A confidentiality review of this kind fits inside a broader contract review engagement covering the full Japan contract checklist.
Frequently Asked Questions#
Can we rely on Japan's general duty of good faith instead of writing a confidentiality clause?
Relying on the Civil Code's good-faith duty alone leaves you without a specific, provable obligation to point to if information leaks. Courts apply good faith case by case after a dispute arises, a weak substitute for a clause that defines what is confidential, who can see it, and what happens on breach before any leak occurs.
If we already have an NDA from the negotiation phase, do we still need a confidentiality clause in the final contract?
Usually yes, because the negotiation NDA was written for a different scope and time period. The final contract should either carry its own confidentiality clause covering performance-stage information or expressly state that the earlier NDA continues to apply and for how long, so the two documents do not overlap without a clear line between them.
Does marking a document "Confidential" automatically make it a protected trade secret under Japanese law?
A marking alone does not satisfy the three-part test under the Unfair Competition Prevention Act. The information also has to carry real commercial usefulness and stay unknown to the public, and the secrecy management has to show up as consistent access controls and handling, backed by more than a cover-page label.
This article is informational only and does not constitute legal, tax, or regulatory advice. Consult a qualified advisor before acting on the content. Last updated: October 2026.