Ostrovsky A.N. gave concise scenic definitions to all his plays. One of his genre was dramatic etude. Many critics voiced their negative attitude towards his play ‘An unexpected incident’. They reproached the playwright for the content lacking profundity and weak plots. They considered the play to be a tentative sketch of a fledgling playwright. The author of the article reviews the attitude towards ‘small genres’ which revealed themselves in the plays of Ostrovsky. The analysis of the play ‘An unexpected incident’ makes it possible to claim that dramatic etude is an independent genre in Ostrvsky’s works which epitomizes the traditions of Russian and foreign drama and becomes close to the art of painting due to its technique, content and ways to reproduction of reality.