difficulty of contract performance and its effect

abstract the theory of hardship is a situation in which the implementation of contractual obligation, as a result of unpredictable events that are out of control, becomes economically difficult and expensive without being physically impossible and distorts the balance of the contract. in such a situation, the hardship theory is applied to restore the balance of the contract. this matter has various titles in several legal systems such as unpredictability theory and sever and unexpected hardship. however, the approach of different legal systems is not equal in the same situation. even though all legal systems agree more or less that in such situation the binding nature of the contract is unjust and justify their position by various basses, the solution of these systems and their bases are different. some legal systems tend to solve the problem by granting exemption and have adopted the dismissal resolution and some of them have adopted the adjustment of the contract. the current study aims to examine these effects and the best effect and maintenance of the best effect (adjustment of contract) which is compatible with the contract rules and principles as well as the concept of hardship theory.