Abstract
Customary law is one of two principal sources of international law, side-by-side international treaties. Mainstream academic studies of customary law often look at the case law of international courts and tribunals, or at least the application of customary law by national courts of larger countries. The purpose of this article is to take a different angle. The author analyses publicly available practice of Latvian courts to see how national courts face the challenge of applying customary law. A source of international law that is intrinsically linked to the challenge of determining its scope. The article shows that for national courts in Latvia, scrupulous application of customary law is not an easy task, and courts do not perform an in-depth analysis of state practice. Instead, national courts prefer different shortcuts, e.g., analysis provided in academic writings or works of the International Law Commission.