This contribution to the YIDFF 2019 catalog on interwar documentary considers Ueno Kozo's role as not just a filmmaker but also as a theorist in the 1930s. Despite tendencies to denigrate theory in the Japanese filmmaking world, Ueno is one example of many directors conceptualizing cinema as they made cinema. Often reviewing the theoretical writings of others, Ueno cited problems in the categories they used, and attempted to clarify those categories by rethinking the relation of cinema to cognition and foregrounding the difference between artistic and scientific cognition. I conclude that despite Tosaka Jun's criticism of Ueno, the two actually shared much in relating representation and cognition. Both the English original and the Japanese translation were published.