Abstract
There is legal relation between both parties after contract formation. The parties are liable for performing each duties but a party is not liable for a failure to perform the duties if party proves that the failure was due to the force majeure. The forec majeure has different concepts and legal principles such as change circumstance, hardship, frustration, impediment and so on. Therefore, it need to analyze a historical background and their presence in various domestic legal systems. Although the CISG describes Art. 79 impediment instead of using the force majeure, the impediment has several interpretative limitation. The CISG pursue to harmonize divergent legal concepts and principles from various national laws and legal systems but the harmonization of legal systems make the impediment more confused. The article goes on to analyzes about limitation of the impediment and reviews to examine the force majeure and hardship in PICC. Thus both parties of international contract insert hardship clause in order to prevent the problem of judgment in a court or a court of arbitration under impediment of CISG.