counterclaim in practice of international court of justice

One of the most important legal issues which is mentioned in rules of ICJ is Counterclaim. This issue is mentioned in rules of both permanent international court of justice and ICJ and now is noticed in article 80 of rules. Article 80 considers two elements that if a claim enjoys them, it will be called counterclaim, these two elements are Direct connection with the subject matter of the claim and “Jurisdiction over the counterclaim. But this article does not explain the details and does not illustrate what does it mean about the conditions. Inspite of all of the reforms and reviews which is done, This general statement spawned the legal ambiguity that when and how ICJ recognizes a claim as counterclaim. Nevertheless, ICJ by it´s practice could answer to these ambiguity and established relatively complete regime for concept of counterclaim. ICJ for recognizing the first element, considers facts, common legal facts,legal aims and for the second element consider the reaction of the respondent of the counterclaim.