Research and development in private law

Research and development in private law

The Requisites of Long-term Contracts With an emphasis On the Principles of International Contracts

Articles in Press

Document Type : Original Article

Authors
seyyed mohammad Yaser mousavi 1
Habib Talebahmadi 2
1 Ph.D. student in Private Law, Faculty of Law and Political Science, Shiraz University
2 Assistant Professor, Department of Private and Islamic Law, Shiraz University, Shiraz
10.22034/jpl.2026.2075518.1256
Abstract
Abstract

In The Fourth Edition of The Principles of International Commercial Contracts, (2016) There is a Particular Focus on Special rules governing Long-term Contracts. Before That, the mentioned Principles included Provisions Concerning Contracts made For Performance within a Specified Period, but did not Systematically address Long-term Contracts. The Present research, with a descriptive and analytical methodology, concludes that Long-term Contracts, due To Uncertainty, they require flexibility and adaptation to new Circumstances. If the governing Conditions of the Contract Undergo Fundamental Changes and the Performance of Obligations becomes difficult, The Parties may renegotiate The Contractual terms. In Case Of disagreement, the dispute resolution authority Can adjust Or Terminate the Contract. Due to the relational Character of Such Contracts, adherence to the Principles Of good faith and mutual Cooperation Throughout all Stages is deemed indispensable. In The interpretation and gap-Filling of Long-term Contracts, One must move beyond Literal meaning of the text and Pay attention to the real intention Of the Parties. The Use Of alternative mechanism for Payment and delivery is Common in These Contracts, and in Case Of breach, While the injured Party's right to immediate Termination is restricted, the breaching party is granted an Opportunity To remedy the default. All remedies for breach Of Contract are Cumulative with Compensation For damages; however, calculating damages in Long-term Contracts is not Straightforward. Respecting human rights requirements and environmental Protection are integral Pillars of Long-term Contracts. Long-term contracts, by creating a steady cash flow in payments, lead to greater stability and consistency in the exchange relationships between parties and result in reduced transaction costs. Proper management of such contracts fosters transparency in relationships and will minimize risks.The absence of conflicts of interest, in line with the prevailing economic rationality in this type of contract, causes long-term contracts to be designed incompletely while establishing a general framework to adapt to potential future changes, allowing contractual gaps to be filled later through alternative mechanisms.
Keywords
Keywords: Long-term Contract
short-term Contract
Continuous contract
Contract Duration
Principles Of international Commercial Contracts
Subjects
A)Books:
1.Akhlaghi,Behrooz & Emam,Farhad,(2018),Unidroit Principles Of International Commercial Contracts,6th edition,Tehran: The SD Institute Of Law Research and Study.(in Persian)
2. Bigdeli,Saeid,(2023),La Révision du Contrat,5th edition,Tehran: Mizan Legal Foundation.(in Persian)
3.Brodermann,Eckart,(2023),Unidroit Principles Of International Commercial Contracts an Article-by-Article Commentary,2nd edition,Germany:Nomos Verlagsgesellschaft,Barden.
4.Darabpour,Mehrab,(1998),Doctrine Of Mitigation Of Damages,1st edition,Tehran:Ganjedanesh Publishing.(in Persian)
5.Dharmananda,Kanaga & Firios,Leon,(2013),Long-Term Contracts,Australia,Sydney:The Federation Press.
6.Furmston,Michael;Tolhurst,Gregory & Mik,Eliza,(2016),Contract Formation,2nd edition,Oxford:Oxford Legal Research Library.
7.Gue,peng,(2022),Good Faith in Long-Term Relational Supply Contracts in The Context Of Hardship From A Comparative Perspective,Springer Nature Singapore Pte Ltd.
8.Habibi,Mahmoud,(2018),Interpretation Of International Commercial Contracts,3th edition,Tehran:Mizan Legal Foundation.(in Persian)
9.Katouzian,Nasser,(2009),Iranian Civil Law:General Principles Of Contracts,vol V,8th edition,Tehran:Enteshar Publication Co.(in Persian)
10.Katouzian,Nasser,(2016),Iranian Civil Law:General Principles Of Contracts,vol I,13th edition,Tehran:Enteshar Publication Co.(in Persian)
11.Kotz,Hein,(1935),European Contract Law,Translatd by:Valiollah Ahmadvand & Others(2005),1st edition,Tehran:Jamejam Publishing Co.(in Persian)
12.Lewison,Sir Kim,(2015),The Interpretation Of Contracts,6th edition,Sweet & Maxwell.
13.Lowenfeld,Andreas F,(1930),International Economic Law,Translated by:Mohammad Habibi Mojandeh(2013),2nd edition,Tehran:Jangal Publishing Co.(In Persian)
14.Macneil,Ian R,(1980),The New Social Contract:An Inquiry into Modern Contractual Relations,New Haven & London:Yale University Press.
15.Macneil,Ian R,(2001),The Relational Theory Of Contract,London:Sweet & Maxwell.
16.MacMillan,Catharine and Stone,Richard,(2012),Elements Of the Law Of Contracts,London:University Of London.
17.Mosavi Bojnourdi,Mirza Hassan,(1992),The Rules Of Islamic Jurisprudence,Vol4,2nd edition,Qom:Ismailian Publishing Co.(in Arabic)
18.Nematollahi,Ismail,(2024),An Introduction to A Comparative Study Of Damages for Breach Of Contract in Common Law,Civil Law and Iranian Law,1st edition,Tehran:The SD Institute Of Law Research & Study.
19.Ostadi,Mona,(2025),Legal Status and Effects Of Open Contract,2nd edition,Tehran:Mizan Legal Foundation.(In Persian)
20.Rajabi,Eisa,(2024), Developments Of Contractual Excuses in International Instruments and Legal Systems by Considering the Oil and Gas Contracts,1st edition,Tehran:Majd Publishing.(in Persian)
21.Schmitthoff,Clive M,(1990),The Law & Practice Of International Trade,Translated by:Behrooz Akhlaghi and Others,Vol1,7th edition,Tehran:The Organization for Researching and Composing University Textbooks in the Humanities(samt).(in persian)
22.Shiravi,Abdolhossein,(2023),International Trade Law,14th edition,Tehran:The Organization for Researching and Composing University Textbooks in the Humanities(samt).(in persian)
23.Shiravi,Abdolhossein,(2024),Oil and Gas Law,6th edition,Tehran:Mizan Legal Foundation.(in Persian)
24.Talebahmadi,Habib,(2013),Pre-Contractual Liability,1st edition,Tehran:Mizan Legal Foundation.(in Persian)
25.Unidroit Principles Of International Commercial Contracts,(2016),Rome:International Institute for The Unification Of Private Law.
26.Vogenauer,Stefan,(2015),Commentary On The Unidroit Principles Of International Contracts(PICC),2nd edition,Oxford University Press.
27.Woss,Herfried;San Roman Rivera,Adriana;Spiller,Pablo T & Dellepiane,Santiago,(2014),Damages in International Arbitration Under Complex Long-Term Contracts,Oxford University Press.
B)Articles:
28.Abdollahi,Mohsen;Sobhninia,Mojtaba & Poorhashemi,Abbas,(2023),Identification Of Jus Cogens Norms Of International Law With a Glance to the Possibility Of Emergence Of Jus Cogens Norms Of International Environmental Law. Human & Environment Journal,64,19-33.(in Persian)
29.Barton,Thomas D;Helena Haapio & Tatiana Borisova,(2015),Flexibility and Stability in Contracts,Lapland Law Review,2,8-26.
30.Bantekas,Ilias & Al-Ahmed,Ahmed,(2023),Contract Law Of Qatar,United Kingdom:Combridge University Press.
31.Campbell,David & Harris,Donald,(2005),Flexibility in Long-Term Contractual Relationship:The Role Co-Operation,Lean Construction Journal,2(1)
32.Catterwell,Ryan,(2023),Co-Operation and Prevention in Contract Law,Melbourne University Law Review,47,115-153.
33.Chetwin,Maree,(2014),Relational and Discrete Contracts and Remedies Requiring Supervision:Same Principles?,Western Australia Law Review,38(1),80-99.
34.Darabpour,Mehrab,(1998),Floating Price,Legal Research Quarterly,1(21,22),221-283.(in Persian)
35.Ebrahimi,Seyyed Nasrollah & Heydari Roochi,Niloofar,(2023),Examining Concept and Nature Of Gas Price Review Clauses,Journal Of Research Energy Law Studies 9(1).60-78.(in Persian)
36.Ebrahimi,Seyyed Nasrollah;Farkhani,Hedayat & Tajarlou,Reza,(2024),Comparative Study Of Force Majeure Clause in Upstream Oil and Gas Contracts in Iran and Common Law Legal System,Journal Of Research Energy Law Studies,9(2),358-376.(in Persian)
37.Feinman,Jay M,(2000),Relational Contract Theory in Context,Northwestern University Law Review,94(3).737-748.
38.Ghasemihamed,Abbas,(2007),Good Faith in Contracts,the basis for the Obligation to be honest and the Obligation to be honest and the Obligation to Cooperate in French Law,Legal Research Quarterly,10(46),99-126.(in Persian)
39.Giancaspro,Mark,(2014),The Rules for Contractual Renegotiation:A Call for Change,The University Of Western Australia Law Review,37(2),1-30.
40.Gounari,Zoe,(2021),Developing A Relational Law Of Contracts:Striking A Balance Between Abstraction and Contextualism,Legal Studies,41,177-193.
41.Haneef,Ahmad Haneef & Jalali Mohammad,(2023),The necessity Of reviewing the Concept of Fundamental Human Rights as Peremptory Norms Of International Law(Jus Cogens),Legal Research Quarterly.25(100).227-245(in persian)
42.Hivvid,Morten,(1999),Long-Term Contracts and Relational Contracts,The Encyclopedia Of Law and Economics,University Of East Anglia,111,46-72.
43.Joachim Bonell,Michael,(2015),The Unidroit Principles Of International Commercial Contracts and Long-Term Contracts International Institute for The Unification Of Private Law(UNIDROIT) Position Paper Prepared For Working group On Long-Term Contracts,1-14.
44.Kazemi,Mahmoud;Taghizaadeh,Ebrahim & Ahmadibayazi,Ali,(2020),Survival Clause:A Comparative Study in Islamic and French Law.Comparative Law Review,11(1),245-270.(in Persian)
45.Kohler,Ben,(2024),Long-Term Contracts in the 2016 Unidroit Principles Of International Commercial Contracts,Edward Elgar Publishing,151-164.
46.Macchiavello,Rocco,(2022),Relational Contracts and Development,Annual Review Of Economics,14,337-362.
47.Macneil,Ian R,(1978),Contracts:Adjustment Of Long-Term Economic Relations Under Classical Neoclassical,and Relational Contract Law,Northwestern University Law Review,72(6),854-905.
48.Mohaghegh Damad,Seyyed Mustafa & Rostami,Mohammadhadi,(2024),Economic analysis Of the Causes and effects Of incomplete Fixed-Term Contracts and their Solutions in Iranian Law (a Comparative Study With a jurisprudential approach),Journal Of Private Law Teachings Of Islamic Countries,1(2),8-25.(in Persian)
49.Mohammadi,Pejman;Sadeghi,Mahmoud & Zolghadr,Mohammad Javad,(2025),Comparative Study Of the Impact Of Contractual Assignment On Third Parties In Iranian and American Law,Journal Of Research and Development in Private Law,2(4),210-238. Doi: 10.22034/jpl.2025.2067233.1224 (in Persian)
50.Mosavi,Fazlolah;Mosavi,Mehdi;Vakili Moghadam,M.Hossein & Golami,Mehdi,(2012),The Principles Of Interpretation Of Contract(A Comparative Study),Journal Of Private Law,1(1),183-213.(in Persian)
51.Mouttotos,Nicholas,(2024),The Unidroit Principles On International Commercial Contract and Sustainable Development,Uniform Law Review,29(2).
52.NikBakht,Hamid Reza,(1997),The Effects Of Force Majeure and Frustration Of Contract,International Law Review,21,95-144.(in Persian)
53.NikBakht,Hamid Reza,(2005),A Review Of Regulating Governmental Contracts in Commercial International Law,Specialized Journal Of Theology and Law,1(15),17-50.(in Persian)
54.Norrgard,Petra Sund;Kolehmainen,Antti & Suhonen,Onerva-Aulikki,(2015),The Principle Of Loyalty and Flexibility in Contracts,Lapland Law Review,2,198-208.
55.Pannebakker,Ekaterina,(2024),Sustainable Development Clauses in International Contracts Through the Lens Of the Unidroit Principles,Uniform Law Review,29(2),352-361.
56.Parsapour,Mohammad Bagher & Zakerinia,Hanieh,(2015),Sorts,Provisions and Effects Of Non-Performance Contract Excuses(Comparative Study On Iranian Legal System,Romano-Germanic,Common Law and Some International Instruments),Comparative Law Researches,19(2),25-50.(in Persian)
57.Pedamon,Catherine & Vassileva,Rodoseveta,(2019),The Duty to Cooperate in English and French Contract Law:One Channel,Two Distinct Views,Journal Of Comparative Law(wildy),14(1),1-25.
58.Pilvar,Rahim & Sari,Mohammadreza,(2024),Causes Of Pathological Clauses in International Commercial arbitration and Ways  to deal with them by looking at WIPO arbitration Clause,Journal Of Research and Development in Private Law,1(1),79-109. Doi: 10.22034/jpl.2024.718551 (in Persian)
59.Rajabi,Abdollah & Seyed Ahmadi Sajjadi,Seyed Ali,(2024),Methodes Of Contract Determination.Comparative Law Researches,28(2),37-63.(in Persian)
60. Robertson,Donald,(2008),Long-Term Relational Contracts and the Unidroit Principles Of International Commercial Contracts.Australian International Law Journal,185,Symposium Paper Presented at the CLE Seminar,Sydney Law School,185-192.
61.Safai,Seyyed Hossein,(1985),Force Majeure:An Overview Comparative Law and International Law and International Commercial Contracts,International Law Review,3(3),111-149.(in Persian)
62.Schlechtriem,Peter,(1999),Termination and Adjustment Of Contracts,European Journal Of Law Reform,Kluwer Law International,1(3),305-323.
63.Schwenzer,Ingeborg & Munoz, Edgardo,(2019),Duty to Renegotiate and Contract Adaption in Case Of Hardship Uniform Law Review,24(1),149-174.
64.Shoarian,Ebrahim,(2011),The Duty Of Obligee to Cooperate in Contract Performance,Journal Of Private Law,8(1),109-137.(in Persian)
65.Shahidi,Mahdi & Bariklou,Alireza,(2002),Restraint Of Trade Contract,Journal Of Comparative Law,2,5-22.(in Persian)
66.Shiravi,Abdolhossein & Shabani Jahromi,Farideh,(2017),Renegotiation Process Of The Investment Contracts,Comparative Law Research,21(3),109-124.(in Persian)
67.Talebahmadi,Habib,(2024),Flexibility in Contracts,The Judiciary's Law Journal,88(125),219-245.(in Persian)
68.Ulfbeck,Vibe & Hansen,Ole,(2022),Sustainability Clause in an Unsustainable Contract Law,European Review of Contract Law,16(1),186-205.
69.Veneziano,Anna,(2010),Unidroit Principles and Cisg:Change of Circumstances and Duty to Renegotiate according to the Belgian Supreme Court,Uniform Law Review,15(1),137-151.
70.Viven-Wilksch,Jessica,(2023),The Importance Of being Relational:Comparative Reflections on Relational Contracts in Australia and The United Kingdom,Northern Ireland Legal Quarterly,74(3),528-558.
71.Zhang,Yanan & Ahtonen,Riitta,(2015),Flexibility in Contracts and Contractual Practice:Empirical Study in China, Lapland Law Review,2,55-97.
72.Zuniga Peralta,Raul F,(2021),Long-Term Contracts and the Unidroit PICC: Towards a Realistic Regulation,Uniform Law Review,26(3),492-531.
73.Zwolankiewicz,Agata,(2021),Hardship and Force Majeure as Grounds for Adaptation and Renegotiation of Investment Contract,Erasmus Law Review,14(2),96-103.