Boris Tomaševskij (1890 – 1957) is among the formalists currently cited whose book Theory of Literature. Poetics (1925) is considered a canonical text of the movement. However, he is studied very little in Russia or abroad. Nevertheless, Tomaševskij was one of the most active participants in Russian formalism and one of its most steadfast defenders. This article seeks to remind us of his original contribution to the study of verse and then to show how much he stands by the evolution of Opojaz. His example also makes it possible to take another look at the split between formalism in St Petersburg and in Moscow. Tomaševskij left a mark on the history of the Moscow Linguistic Circle; thanks to his work on quantitative metrics, he is close to the Moscow formalist Boris Yarxo (1889 – 1942), who applied similar methods to the study of Western classic theater (Corneille). While Tomaševskij left no theoretical article systematizing his research, it remains that his texts contain bold statements that are still waiting for a commentary.