The case law and doctrine in Germany have created the concept of the essential competence (wesenseigene Zuständigkeit) for the cases where the applicable foreign law orders to the court to perform the actions are not compatible with the essence of the court in German law. The article is dedicated to that theory. First of all, this article has a task to establish whether that theory has the right to exist. To solve this task it is dealt with the spectrum of the cases in the German judicial decisions in which the question of the essential competence was arisen. The cases in which the court has to take evaluative decision, in which the subject of claims unknown to lex fori and in which the spouses wanted to get divorced according to the islamic law having religious origin, all these cases can be dealt by the German court and so they are covered by the essential competence of the German court. The German literature and after all the German courts have decided like this. But only one, very rare, the case of the divorce according to the religious Jewish law which is still the positive law in Israel can be true example of the absence of the essential competence (lack of machinery). Indeed, the applicable substantive (religious Jewish) law requires that the court should take part in a religious ritual, the thing, which cannot be provided by a secular court. For this rare case is set the second task: to establish the place of the essential competence in the system of the judicial competence. Having rejected the options of the distinction of the competence between branches of judicial power in the State and of the special subject competence, the author agrees which the prevailing view according to which that is the kind of the international competence, i.d. the distinction of the competence between the systems of domestic and foreign courts making a comment that the foreign courts are not any, taken abstractly court, but only the religious court of the defined country, whose lex causae is to be applied in this case according to the choice of law-rule of the court.