The Right Bank Ukraine has been a battlefield of different nationalizing forces in the course of the nineteenth century. Arguing against nationalist historiography that depicts the Tsarist policy in the Right bank Ukraine as occupation, the Japanese scholar Kimitaka Matsuzato demonstrates that if it was so, the thrust of the oppression was aimed at the Poles and the Jews rather than Ukrainians, whom the officialdom considered to be Russian. The famous “Polish factor” helped to develop among “Russians” in the Western Borderlands a sense of Russianness more acute than anywhere else in the Empire. This article tangles with the problem of what was this factor in terms of culture, language, economics and politics. Based upon diverse empirical material and enriched with nuanced methodological approaches including a theoretical scheme of ethnic domination in the Empire, this article is a valuable contribution into the ongoing debate on the history of nationalities in the Western Borderlands of the Russian Empire. Additionally, the article incorporates some of the research done by Japanese historians, which is not always readily available both for Russian/CIS and American/European academic audience.