Evidence Contract and its Limits: The Validity of The “Only One Party’s Evidence is Admissible” Clause in Contracts

Evidence Contract and its Limits: The Validity of The "Only One Party's Evidence is Admissible" Clause in Contracts

Zeynep DURAN
Legal Intern


In practice, especially in commercial transactions and contracts, clauses stating that only one party’s commercial books and records will be evidence are frequently included. Especially in cases where one party is in a dominant position and the other party cannot say “no”, such clauses are widely used. For this reason, on the one hand, the fact that both parties sign as prudent merchants suggests that the clause will be valid, but on the other hand, it causes hesitation due to the fact that the provision disrupts the balance between the parties to an excessive extent and restricts the court’s ability to act.

In this article, firstly, the legal basis of the evidential contract will be explained, and then the limits of the evidential contract will be discussed. Then, the issue of whether the provisions of the evidential contract are in fact valid when they are widely used in commercial contracts will be evaluated in the light of precedent judicial decisions. In this article, the limits of the evidential contract will be discussed in the context of commercial transactions. No evaluation will be made in terms of other areas of law.


In civil proceedings, the parties who have a dispute between them apply to various evidences in order to prove their claims. This is due to the necessity of the matter, because in our legal system, where the principle of submission by the parties exists with some exceptions, the judge cannot automatically take into account what one of the parties has not put forward. As such, the parties concretize their claims arising from a dispute that has already occurred or is ongoing between them through evidence, and form an opinion before the judge. The ability of the parties to rely on evidence for their claims is also a part of the right to a fair trial and the freedom to seek rights. Therefore, the right of proof has a very important place in our law.

It is of great importance which evidence the parties may use when exercising this right. Our law restricts the right of proof by stating that the parties may use the right of proof in accordance with the specified time and procedure, and that evidence obtained unlawfully may not be brought forward, and that the matters that the law orders to be proved by certain evidence may not be proved by other evidence. Therefore, the parties are exposed to certain obstacles while exercising their statutory right of proof. In addition, the legislator has introduced a provision under Article 193 of the Code of Civil Procedure No. 6100 under the name of evidential agreement. The aforementioned provision is regulated as follows; “The parties may agree that the facts that are foreseen to be proved by certain evidence in the law may also be proved by other evidence or evidence, or may limit the proof of the facts that are not foreseen to be proved by certain evidence by certain evidence or evidence”.

Therefore, through the evidential contract, the parties are no longer bound by the provisions of the statutory right of proof and have the opportunity to determine the evidence that they may put forward regarding the disputes that may arise between them. However, it is important to note here that this agreement does not provide unlimited freedom to the parties. As a matter of fact, this point is underlined in Article 193, paragraph 2 of the Code of Civil Procedure. According to the aforementioned provision, the provisions of the contract that make it difficult or impossible for one of the parties to exercise the right of proof are deemed invalid by the legislator.


Unlike public law, where there is no principle of equality, in private law, the parties are on an equal footing and are also freer in terms of freedom of will. Therefore, persons who are parties to a private law relationship have the freedom to establish contracts among themselves. Although the evidential contract regulated under Article 193 of the Code of Civil Procedure No. 6100, which is the subject of this article, is a result of this freedom, there are some limits to this freedom.

In fact, making an evidential contract is a right granted to the parties within the scope of the freedom of contract under Article 48 of the Turkish Constitution. With this agreement, the parties may agree that one or more evidence may be used in addition to the evidence specified in the law for the resolution of existing or potential disputes between them, or that they may resort to other evidence or evidence, even if not regulated by law. However, while agreeing on the evidence or evidence, the parties should not include evidence that has been/will be obtained illegally within the scope of the agreement. Even if they do, the judge will not take this evidence or evidence as a basis for the judgment despite the existence of the agreement. In addition, evidence that has not been duly submitted will not become valid just because it is written in the contract.

However, the dispute that forms the basis of the evidential contract must be certain or determinable. Such an arrangement has been made based on the fact that binding all kinds of disputes that may arise between the parties to a contract may lead to various loss of rights. Again, it should be kept in mind that the evidential contract cannot be used in disputes where the principle of ex officio investigation exists, but may be in question in disputes where the principle of production by the parties exists.

On the other hand, the parties should not interfere with other rights while exercising a right granted to them, namely the freedom to form a contract. Since the freedom to form a contract is a principle inherent in private law, it should be prevented that the parties who have equal rights with this contract are weakened against each other due to the equal status of the parties in private law relations.

The main right that may be violated by the evidential contract is the right to a fair trial and the rights that are related to the evidential contract are the right to be heard, the right to proof and the principle of equality. These rights are so important that they should not be eliminated by any contractual provision. In the absence of these rights, people’s confidence in justice will be undermined, the right to vindication will become widespread in society, and in the long run, the state will cease to be a state of law. For this reason, behaviors that touch the essence of these rights should not be valid, even if they are manifested in the form of the parties’ joint declaration of will, in other words, freedom of contract.


Within the scope of these explanations, while non-exclusive evidence agreements, which we call expansive evidence agreements, are out of the discussions since they do not limit the parties’ right of proof, on the contrary, they give them freedom, narrowing evidence agreements, which we call exclusive, limit the right of proof of one of the parties in various ways, so it is necessary to approach evidence agreements of this nature cautiously.

Therefore, it is necessary to make an assessment in terms of the validity of narrowing-effect evidential agreements. The first step of this evaluation is to determine the limits of the limitation of the right of proof. This issue is explained in Article 193/f. 2 of the Code of Civil Procedure. Article 193/f. 2 of the Code of Civil Procedure stipulates those evidential agreements that “make it impossible or extremely difficult for one of the parties to exercise the right of proof” are invalid. This provision is indeed a reflection of the right to a fair trial and is a proper regulation. However, it is very difficult to distinguish which contractual provisions render a party’s right of proof impossible or extremely difficult. Due to both the breadth of the right of proof and the diversity of the evidential agreements to be made by the parties, it is not possible to make an exhaustive enumeration in this regard. As a matter of fact, the legislator has not made a census. Therefore, the distinction in question should be made separately according to the concrete event and case, within the framework of the principle of honesty in Article 2 of the Turkish Civil Code No. 4721, based on the opinions in the doctrine and the jurisprudence of the court, and stereotypical evaluations should be avoided.

On the other hand, the evidential agreement may be prepared by the parties as a standalone agreement, or it may be included as an article in a large number of pre-prepared contract samples for future use, which we call general transaction conditions.

In this case, as it is seen in practice, it is important to distinguish whether the right of proof of the party in question is limited or not, especially since the party offering general terms and conditions is already weaker than the party offering them. For this reason, Article 193/f 2 of the Code of Civil Procedure and the general terms and conditions provisions of the Code of Obligations (Turkish Code of Obligations 20 et seq.) should be taken into consideration together. Evidence agreements that contradict these provisions will be deemed unwritten, in other words, invalid. In practice, organizations such as banks, insurance agencies and telecommunication companies mostly resort to this method. In order to save time and bear as little responsibility as possible in case of possible disputes, they have their customers sign pre-prepared documents before the transactions to be carried out. Since the legal knowledge of these organizations, which we can call prudent merchants most of the time, cannot be compared with the legal knowledge of a citizen, the legislator has made such a regulation as it may cause various damages for the person to be bound by the provisions of the contract determined by one party written on the document.

In the event that the evidential contract is used in contracts where consumer transactions are the subject of consumer transactions, the evaluation of the contract in terms of the right of proof will come to the forefront, especially since the consumer is in need of protection and the right of proof of the consumer should not be limited and weakened. Therefore, in such an evaluation, although Article 193/f 2 of the Code of Civil Procedure is the main provision to be applied, Article 5 of the Regulation on Unfair Terms in Consumer Contracts should also not be forgotten.


As a result, it is quite appropriate that a type of contract called evidential contract is regulated in our law. In civil procedural law, which is a sub-branch of private law, it is extremely important for the parties to be able to determine the evidence to be used in the claims and defenses they will put forward in the existing or potential disputes between the parties through the evidential contract, which is a reflection of their common declaration of will, as well as to conclude contracts on any subject, provided that they are not contrary to law and morality, in order to direct the course of the proceedings.

However, whether such an important agreement limits the right of proof of one of the parties is also a matter that the judge hearing the case should consider in order to prevent a possible loss of rights. However, while making this assessment, general ideas should be avoided and the judge should act according to the characteristics and conditions of the concrete case. The judge should carefully and diligently examine the parties to the contract, the purpose of the contract, the provisions of the contract, whether the provisions of the contract in question violate the principle of proof, the right to be heard and the principle of equality, and whether they are contrary to the rule of honesty. With such an assessment, the free will of the parties in the evidential contract, which is a principle of private law, will be preserved and the principle of equality of the parties in private law will not be harmed.

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