Evolution of Counterclaim in Procedure and Jurisprudence The International Court of Justice

Since the first time, that is to say the codifying of the first Rules of the  Permanent Court of International Justice (hereinafter PCIJ) that the condition of counterclaims was included in 1922 up to now, the regulations as to these claims have been subjected to repeated amendments. Besides, the jurisprudence, through detecting existing lacunas regarding counterclaims, have could notably put this conception into change. According to the last version of the Rules of Court, admissibility of a counterclaim necessitates two conditions. First is the court’s jurisdiction, and the other is connection between the counterclaim the main claim. This article aims to investigate the evolutions emerged in this context in the light of Rules and jurisprudence of the PCIJ and International Court of Justice (hereinafter ICJ). Based on the last changes of the rules of court and giving the jurisprudence, it could be said that a counterclaim, in spite of being related to the main claim, is an independent claim which gives the respondent the opportunity and right to not only reject the plaintiff’s claim, but also introduce a new one.