This work is devoted to the analysis of iki as a Japanese aesthetic category. The author examines the history of the origin of this concept, related to the daily life of the merchant class of Japan in the Edo era. Special attention is paid to the work of the Japanese philosopher Kuki Shuzo "The Structure of Iki which the author recognizes as the first scientific work dedicated to the phenomenon of iki. The article points to the importance of Kuki’s research for the further development of aesthetics, as well as its influence on the philosophy of the German thinker M. Heidegger. The author draws parallels between the understanding of the concept of iki in Kuki and M. Heidegger. In conclusion, the article describes the modern criticism of the work "The Structure of Iki which is primarily associated with a rethinking of the phenomenon under consideration. The author recognizes the need for further research in the field of Japanese aesthetics, in particular, the concept of iki.