The article investigates the problem of the typology of opening fragments of the detective narrative, based on the works of Arthur Conan Doyle about Sherlock Holmes and Dr Watson. The author distinguishes three types of these fragments and some subtypes in each of them. The analysis deals with both the synchronic (types of the beginnings) and in the diachronic (evolution of the beginnings) aspects in five chronological sections of Holmes' saga by Doyle.