Contracts Law
This section covers the core institutions of the law of obligations — from contract formation to termination, from performance to adaptation. The articles are prepared in light of the Turkish Code of Obligations (No. 6098).
Impossibility of Performance and Termination of the Obligation: TBK m.136-137
Absence of fault, partial impossibility and restitution
How does impossibility of performance extinguish the obligation, and how does liability in damages arise where the impossibility is fault-based? A comprehensive analysis under TBK m.136-137.
Performance of an obligation may become impossible after contract formation. Where the impossibility is attributable to the debtor's fault, liability in damages arises; where it stems from a cause not imputable to the debtor, the obligation is extinguished and the reciprocal performances are unwound. TBK m.136 and m.137 regulate these two typical outcomes separately.
Full Impossibility of Performance — TBK m.136
Under TBK m.136/1, where the performance of an obligation becomes impossible for reasons for which the debtor is not responsible, the obligation is extinguished. Impossibility may be physical (e.g. destruction by natural disaster), legal (subsequent prohibition), personal (death of an artist) or economic — although economic difficulty is primarily addressed under the adaptation rule in TBK m.138.
In synallagmatic contracts, the debtor released by impossibility must restore what was received under the rules of unjust enrichment, and loses the right to claim the counter-performance not yet rendered (TBK m.136/2). If the debtor was in default at the time of impossibility, or failed in the duty to give notice of impossibility, the resulting damages must be compensated (TBK m.136/3).
Partial Impossibility — TBK m.137
If performance becomes partially impossible for reasons for which the debtor is not responsible, the debtor is released only from the impossible portion. However, if it is clear that the parties would not have concluded the contract had they foreseen the partial impossibility, the entire obligation is extinguished.
In synallagmatic contracts, where one party's obligation is partially impossible and the creditor accepts partial performance, the counter-performance is rendered in the same proportion. If the creditor refuses partial performance or the counter-performance is indivisible, the rules on full impossibility apply.
Culpable Impossibility and Damages
Where the impossibility is attributable to the debtor's fault, the obligation is not extinguished; the debtor becomes liable for negative or positive damages replacing the original performance (TBK m.112). The debtor bears the burden of proving absence of fault; absent such proof, fault is presumed.
Substitutionary damages represent the monetary value of the original performance. The calculation is based on the difference between the creditor's hypothetical asset position had performance occurred and the actual position resulting from non-performance.
Distinguishing Impossibility from Hardship
Two frequently conflated concepts are impossibility of performance (TBK m.136) and hardship (TBK m.138). Impossibility is the objective inability to perform; hardship is the situation where, although technically still possible, performance cannot reasonably be expected of the debtor due to extraordinary changes in circumstances.
Impossibility extinguishes the obligation automatically; hardship requires the debtor to apply to the court for adaptation or, if adaptation is not possible, rescission. Correctly drawing this distinction directly affects the form of action and the available claims.
Practical Considerations
In contractual disputes, not only the signed text but also offer correspondence, revision history, invoices, delivery records, payment records, formal notices and the parties' subsequent conduct are taken into account. The formation, performance and termination of a contract often acquire meaning only through these ancillary documents.
Form requirements, authority of representation, penalty clauses, exclusion-of-liability provisions, standard terms and consumer-protection rules may all affect the validity or enforceability of a contract. In standard-form documents in particular, the other party must be informed, express acceptance obtained, and onerous provisions specifically highlighted.
Before any dispute arises, the scope of obligations, delivery date, defect notice, default notice, interest and competent-court clauses should be drafted explicitly. Vague provisions may give rise to interpretation disputes and to difficulties of proof later on.
Relevant Statutory Provisions
- TBK m.27Initial impossibility — absolute nullity
Original (Turkish, official):
MADDE 27- Kanunun emredici hükümlerine, ahlaka, kamu düzenine, kişilik haklarına aykırı veya konusu imkânsız olan sözleşmeler kesin olarak hükümsüzdür. Sözleşmenin içerdiği hükümlerden bir kısmının hükümsüz olması, diğerlerinin geçerliliğini etkilemez. Ancak, bu hükümler olmaksızın sözleşmenin yapılmayacağı açıkça anlaşılırsa, sözleşmenin tamamı kesin olarak hükümsüz olur.
English summary (non-binding):
Contracts contrary to mandatory rules, morals, public order or personality rights, or whose subject matter is impossible, are absolutely null. Partial nullity of provisions does not affect the validity of the rest; however, if the contract would clearly not have been concluded without those provisions, the whole contract is null.
Source: mevzuat.gov.tr · last reviewed: 2026-05-12
- TBK m.112Debtor's fault-based liability for breach
Original (Turkish, official):
MADDE 112- Borç hiç veya gereği gibi ifa edilmezse borçlu, kendisine hiçbir kusurun yüklenemeyeceğini ispat etmedikçe, alacaklının bundan doğan zararını gidermekle yükümlüdür.
English summary (non-binding):
Where the obligation is not performed or not performed as required, the debtor is liable for the resulting damage to the creditor, unless the debtor proves that no fault can be attributed.
Source: mevzuat.gov.tr · last reviewed: 2026-05-12
- TBK m.136Subsequent full impossibility
Original (Turkish, official):
MADDE 136- Borcun ifası borçlunun sorumlu tutulamayacağı sebeplerle imkânsızlaşırsa, borç sona erer. Karşılıklı borç yükleyen sözleşmelerde imkânsızlık sebebiyle borçtan kurtulan borçlu, karşı taraftan almış olduğu edimi sebepsiz zenginleşme hükümleri uyarınca geri vermekle yükümlü olup, henüz kendisine ifa edilmemiş olan edimi isteme hakkını kaybeder. Kanun veya sözleşmeyle borcun ifasından önce doğan hasarın alacaklıya yükletilmiş olduğu durumlar, bu hükmün dışındadır. Borçlu ifanın imkânsızlaştığını alacaklıya gecikmeksizin bildirmez ve zararın artmaması için gerekli önlemleri almazsa, bundan doğan zararları gidermekle yükümlüdür.
English summary (non-binding):
Where the performance of an obligation becomes impossible for reasons not attributable to the debtor, the obligation is extinguished. In synallagmatic contracts, the debtor released by impossibility must restore what was received under unjust-enrichment rules and loses the right to claim the counter-performance not yet rendered. Cases where the law or the contract has placed pre-performance risk on the creditor are reserved. If the debtor does not notify the creditor of the impossibility without delay and fails to take measures to limit the damage, the debtor is liable for the resulting damages.
Source: mevzuat.gov.tr · last reviewed: 2026-05-12
- TBK m.137Partial impossibility of performance
Original (Turkish, official):
MADDE 137- Borcun ifası borçlunun sorumlu tutulamayacağı sebeplerle kısmen imkânsızlaşırsa borçlu, borcunun sadece imkânsızlaşan kısmından kurtulur. Ancak, bu kısmi ifa imkânsızlığı önceden öngörülseydi taraflarca böyle bir sözleşmenin yapılmayacağı açıkça anlaşılırsa, borcun tamamı sona erer. Karşılıklı borç yükleyen sözleşmelerde, bir tarafın borcu kısmen imkânsızlaşır ve alacaklı kısmi ifaya razı olursa, karşı edim de o oranda ifa edilir. Alacaklının böyle bir ifaya razı olmaması veya karşı edimin bölünemeyen nitelikte olması durumunda, tam imkânsızlık hükümleri uygulanır.
English summary (non-binding):
Where performance becomes partially impossible for reasons not attributable to the debtor, the debtor is released only from the impossible portion. However, if it is clear that, had this partial impossibility been foreseen, the parties would not have concluded the contract, the entire obligation is extinguished. In synallagmatic contracts, if one party's performance becomes partially impossible and the creditor accepts the partial performance, the counter-performance is rendered in the same proportion. If the creditor refuses such partial performance or the counter-performance is indivisible, the rules on full impossibility apply.
Source: mevzuat.gov.tr · last reviewed: 2026-05-12
- TBK m.138Hardship and adaptation
Original (Turkish, official):
MADDE 138- Sözleşmenin yapıldığı sırada taraflarca öngörülmeyen ve öngörülmesi de beklenmeyen olağanüstü bir durum, borçludan kaynaklanmayan bir sebeple ortaya çıkar ve sözleşmenin yapıldığı sırada mevcut olguları, kendisinden ifanın istenmesini dürüstlük kurallarına aykırı düşecek derecede borçlu aleyhine değiştirir ve borçlu da borcunu henüz ifa etmemiş veya ifanın aşırı ölçüde güçleşmesinden doğan haklarını saklı tutarak ifa etmiş olursa borçlu, hâkimden sözleşmenin yeni koşullara uyarlanmasını isteme, bu mümkün olmadığı takdirde sözleşmeden dönme hakkına sahiptir. Sürekli edimli sözleşmelerde borçlu, kural olarak dönme hakkının yerine fesih hakkını kullanır. Bu madde hükmü yabancı para borçlarında da uygulanır.
English summary (non-binding):
If an extraordinary situation unforeseen and unforeseeable at the time of contract arises from a cause not attributable to the debtor and so alters the facts existing at the time of contract that demanding performance from the debtor would be contrary to good faith, and the debtor has not yet performed (or performed reserving rights based on hardship), the debtor may request the court to adapt the contract to the new conditions; if that is impossible, the debtor may rescind. In contracts with continuous performance, the debtor exercises the right of termination instead of rescission. This article also applies to debts in foreign currency.
Source: mevzuat.gov.tr · last reviewed: 2026-05-12
- TBK m.77Unjust enrichment — legal basis for restitution
Original (Turkish, official):
MADDE 77- Haklı bir sebep olmaksızın, bir başkasının malvarlığından veya emeğinden zenginleşen, bu zenginleşmeyi geri vermekle yükümlüdür. Bu yükümlülük, özellikle zenginleşmenin geçerli olmayan veya gerçekleşmemiş ya da sona ermiş bir sebebe dayanması durumunda doğmuş olur.
English summary (non-binding):
A person who, without justification, is enriched at the expense of another's assets or labour must restore the enrichment. This duty arises in particular where the enrichment rests on an invalid, unrealised or terminated cause.
Source: mevzuat.gov.tr · last reviewed: 2026-05-12
The statutory provisions are reproduced for information purposes only. The current and official text on mevzuat.gov.tr is authoritative.
Conclusion
Impossibility usually entails a two-way unwinding process — establishing the end of the obligation and restoring the reciprocal performances. Correctly identifying the type of impossibility (full/partial, with/without fault) at the outset decisively shapes the form of the action.
This article is for information purposes only and does not constitute legal advice. If you would like professional assistance on a specific matter, you may request a consultation.
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