Watsuji's Koji Junrei is a book of impressions of a trip he took in 1918 to Japan's ancient capital of Nara, where he saw a number of Buddhist temples. By then, Watsuji had already published influential, groundbreaking books on Nietzsche, Schopenhauer, Kierkegaard and the book Gūzū saikō (Resurrection of Idols).
Koji Junrei is significant in that it began a modern literary trend of "travel writing" about ancient temples and shrines in Japan and elsewhere. While the genre had existed for centuries, it was Koji Junrei that almost singlehandedly resurrected it.