Does the CISG apply to a contract with a Turkish supplier?

Yes, by default, if the buyer is also in a CISG state. Turkey is a contracting state, with the convention in force for it since 1 August 2011, and Germany and the Netherlands are parties too. The parties can exclude it under Article 6, and it does not apply where the buyer supplies a substantial part of the materials (Article 3(1)).

How long does a buyer have to report a defect under the CISG?

Within a reasonable time after the buyer discovered or ought to have discovered the defect, and in any case within two years of actual handover, unless a contractual guarantee period is longer (Article 39). The reasonable time is not a fixed number of days.

Does an NDA protect drawings sent to a Turkish workshop?

The NDA is the main protection. Directive (EU) 2016/943 requires reasonable steps to keep information secret before it counts as a trade secret in the EU, and the Turkish Commercial Code lists unlawful disclosure of production and business secrets as unfair competition. Neither replaces a contract with a defined scope, sub-supplier flow-down and a forum you can enforce.

Can a court judgment against a Turkish supplier be enforced in Turkey?

Only if the reciprocity condition of Article 54 of Turkish Law No. 5718 is met for the state that gave the judgment. Arbitral awards fall under the New York Convention, which Turkey joined on 2 July 1992 with reciprocity and commercial-relationship declarations.

Who owns the tooling a buyer pays for?

The contract decides. The CISG does not govern the effect of the contract on property in goods (Article 4). State in an annex that the buyer owns the tooling, list each item, require marking, and set the conditions for its release.

Turkish Supplier Contract: NDA, IP and Warranty Clauses

A manufacturing agreement with a Turkish supplier should fix four things in writing before the first order: who may use your drawings (the NDA), who owns drawings, tooling and process improvements (IP), which law and forum decide disputes, and what the supplier owes when parts fail (warranty and liability). Where buyer and supplier are both in states party to the UN Sales Convention (CISG), as Germany and Turkey are, the convention applies by default unless the contract excludes it, and its notice rules then govern defect claims.

What should a manufacturing agreement with a Turkish supplier cover?

The clauses in Table 1 decide who pays and who may use what when something goes wrong. They fit a framework agreement for parts made to your drawing and can also sit in the general conditions of a purchase order. This article is a drafting checklist for engineers and buyers, not legal advice. Have the final text reviewed by a lawyer who knows the law you choose and Turkish law.

Table 1. Clauses to agree in a manufacturing agreement with a Turkish supplier

Clause	Purpose	Watch for
Confidentiality (NDA)	Keeps drawings, CAD files and specifications secret	Definition of confidential information, sub-supplier flow-down, return or deletion of files
Ownership of IP	Keeps drawings, designs and data with the buyer	Design improvements and process know-how created by the supplier
Tooling and fixtures	Fixes who owns jigs, patterns and gauges the buyer paid for	Marking, listing in an annex, release on termination
Governing law	Names the law that interprets the contract	Whether the CISG is kept or excluded
Dispute forum	Names court or arbitration and the seat	Whether the decision can be enforced against the supplier's assets
Conformity and warranty	Defines a defective part and the remedy	Start of the warranty period, notice period, sorting and rework cost
Liability and insurance	Sets caps and required cover	Intent and gross negligence, product liability cover
Subcontracting	Controls who else handles the part	Written approval, same NDA and quality terms down the chain

Source: Ertaş Engineering drafting checklist. Statutory references are in the sections below.

Which law and forum should the contract choose?

Name the governing law yourself. Article 3(1) of the Rome I Regulation (EC) No 593/2008 says a contract "shall be governed by the law chosen by the parties", and Article 24 of Turkish Law No. 5718 lets the parties choose as well. Without a choice, Rome I points to the supplier's country: a sale of goods follows the law of the seller's habitual residence (Article 4(1)(a)), a contract for services the law of the service provider (Article 4(1)(b)). Either route leads to Turkish law for a Turkish supplier.

The CISG sits on top of that choice. Turkey acceded on 7 July 2010 and the convention has been in force for it since 1 August 2011. Germany (in force 1991) and the Netherlands (1992) are parties; the United Kingdom is not on the UNCITRAL status list. It applies when both parties are in contracting states (Article 1(1)(a)) or when the conflict rules lead to the law of a contracting state (Article 1(1)(b)), and the parties may exclude it (Article 6). It does not apply where the buyer supplies a substantial part of the materials for the parts (Article 3(1)), which matters for free-issue steel or castings. Decide on the CISG deliberately and write the decision into the contract.

On forum, a foreign court clause is valid in Turkey for non-exclusive matters if it is in writing (Law No. 5718, Article 47). Enforcing the resulting judgment against a Turkish supplier needs a reciprocity basis between Turkey and the state of the court (Article 54). Arbitral awards run under the New York Convention, to which Turkey acceded on 2 July 1992, applying it on a reciprocity basis and to commercial relationships only. An arbitration clause with a seat in a Convention state therefore gives a treaty basis for enforcement. Check this point with counsel before you sign. State of the texts: 2026-10-30.

What should the NDA contain?

An NDA is the evidence that you took reasonable steps. Directive (EU) 2016/943 defines a trade secret as information that is secret, has commercial value because it is secret and "has been subject to reasonable steps" to keep it secret (Article 2(1)). That definition governs your side of the border. In Turkey the contract carries the weight, with the Turkish Commercial Code as a backstop: Article 55(1)(d) lists the unlawful disclosure of production and business secrets as unfair competition.

Five points make an NDA usable for a machining supplier:

It defines confidential information to include drawings, CAD and STEP files, specifications, inspection data and the existence of the order, marked or not.
It limits use to producing parts for the buyer, and bans copying, reverse engineering, spare parts for third parties and sale of overruns or rejects.
It requires written approval of every sub-supplier and an equivalent NDA down the chain. The drawing may pass through more than one workshop, and each hand-over is a leak point.
It requires return or certified deletion of files and destruction or return of rejected parts when the relationship ends.
It states a survival period in years that outlasts the supply relationship, with an open-ended duty for information that stays secret.

Add the usual exceptions (public, already known, independently developed) and give the NDA the same governing law and forum as the main agreement.

Who owns the IP in drawings, tooling and process improvements?

The agreement should say that drawings, CAD data, specifications and inspection data belong to the buyer, and that the supplier receives a limited licence to make parts for the buyer. Industrial property rights are national. An EU design or EU trade mark does not give you rights in Turkey, so if a design or patent matters, check what is registered in Turkey itself.

Improvements need a clause of their own. Under Article 73(1) of Industrial Property Law No. 6769, a design made by an employee in the course of the employee's duties belongs to the employer unless agreed otherwise. If the supplier's engineers redesign a feature to make it machinable, the right sits with the supplier by default. Either assign design improvements to the buyer or take an exclusive licence, and keep the supplier's general process know-how with the supplier. Define which is which.

Tooling follows the same logic. List each fixture, pattern and gauge the buyer paid for in an annex, require marking as buyer property, and set the conditions and the time frame for its release, including at termination. The CISG does not settle ownership questions (Article 4), so the contract has to.

How should the warranty clause be written?

Start with what "conforming" means. Under CISG Article 35(1) the seller must deliver goods of the quality and description required by the contract, so the contract documents must include the drawing revision, the general tolerance class (for example ISO 2768-m), the material specification and the inspection certificates. The quality documents for a part type are part of that description.

The notice period matters more than the warranty length, because the rules differ sharply (Table 2).

Table 2. Defect notice and limitation rules that can apply to a Turkish supplier

Regime	Notice of defect	Outer limit
CISG, Article 39	Reasonable time after the buyer discovered or ought to have discovered the defect	2 years from actual handover, unless a contractual guarantee period is longer
Turkish Commercial Code, Article 23(1)(c), commercial sale under Turkish law without the CISG	2 days for defects obvious at delivery; for other defects, examination within 8 days of receipt and notice within that period	Turkish Code of Obligations, Article 231: 2 years from transfer, unless the seller undertook longer; not available to a seller grossly at fault
Turkish Code of Obligations, Articles 477 and 478, work contract	Notice without delay once a hidden defect appears	2 years from delivery for movable works; 20 years if the contractor was grossly at fault

Source: CISG Article 39; Turkish Commercial Code No. 6102, Article 23(1)(c); Turkish Code of Obligations No. 6098, Articles 231, 477, 478. Status as of 2026-10-30.

Two consequences follow. First, if you exclude the CISG and choose Turkish law, an incoming-inspection process that takes two weeks can already miss the statutory notice window, so the contract should set its own inspection and notice period. Second, Turkish law may treat parts made to a buyer's drawing as a work contract rather than a sale (Code of Obligations, Article 470), with different rules from the sale regime. Which one applies is a question for Turkish counsel.

Write these points into the clause:

The warranty period and its start: delivery under the agreed Incoterms rule (see Incoterms 2020 for Turkey to EU) or acceptance after inspection. If it exceeds two years, say that it is a contractual guarantee period in the sense of CISG Article 39(2).
The notice period, counted from receipt or discovery, and the form of notice, such as inspection report with photographs.
The remedies: rework or replacement at the supplier's cost including freight and customs, a credit note, and the cost of sorting and line stoppage.
The response times for containment and root cause, usually an 8D report. See non-conformance and 8D with an overseas supplier.

Do not rely on a liability exclusion for serious fault. Article 115 of the Turkish Code of Obligations makes an agreement made in advance that the debtor is not liable for gross fault void.

How should liability, insurance and recourse be handled?

Set a liability cap per claim and per year that matches the value at risk, and carve intent and gross negligence out of it. Require the supplier to hold product liability insurance and to supply the certificate on request. Name the cover amount in the contract once you know your own exposure.

Recourse is becoming more relevant. Directive (EU) 2024/2853, the new Product Liability Directive, applies to products placed on the market from 9 December 2026; the 1985 regime remains for earlier products. Under the new directive the manufacturer of a defective component can be liable, and an operator who has compensated the injured person can seek recourse from other liable operators under national law. If your machined part goes into a product that causes damage, your own customer may claim against you, and your recourse against the supplier is only as good as the indemnity, insurance and forum clauses you agreed.

Qualify the supplier before you negotiate; the audit checklist for contract machining suppliers in Turkey covers what to verify. How orders run through our audited network in Bursa is described on how we work.

Frequently asked questions

Does the CISG apply to a contract with a Turkish supplier?: Yes, by default, if the buyer is also in a CISG state. Turkey is a contracting state, with the convention in force for it since 1 August 2011, and Germany and the Netherlands are parties too. The parties can exclude it under Article 6, and it does not apply where the buyer supplies a substantial part of the materials (Article 3(1)).
How long does a buyer have to report a defect under the CISG?: Within a reasonable time after the buyer discovered or ought to have discovered the defect, and in any case within two years of actual handover, unless a contractual guarantee period is longer (Article 39). The reasonable time is not a fixed number of days.
Does an NDA protect drawings sent to a Turkish workshop?: The NDA is the main protection. Directive (EU) 2016/943 requires reasonable steps to keep information secret before it counts as a trade secret in the EU, and the Turkish Commercial Code lists unlawful disclosure of production and business secrets as unfair competition. Neither replaces a contract with a defined scope, sub-supplier flow-down and a forum you can enforce.
Can a court judgment against a Turkish supplier be enforced in Turkey?: Only if the reciprocity condition of Article 54 of Turkish Law No. 5718 is met for the state that gave the judgment. Arbitral awards fall under the New York Convention, which Turkey joined on 2 July 1992 with reciprocity and commercial-relationship declarations.
Who owns the tooling a buyer pays for?: The contract decides. The CISG does not govern the effect of the contract on property in goods (Article 4). State in an annex that the buyer owns the tooling, list each item, require marking, and set the conditions for its release.