Aerial photographs, especially those taken before World War II, are valuable documents to know the historical changes in gardens and open spaces. In the academia of photogrammetry and geography, it is an accepted view that the existing aerial photographs of Kyoto City taken before the World War II were taken in 1928; this view is based on the work of Hattori. However, Kyoto Shimbun News (dated December 22, 1993) reported that Shimizu conducted an investigation and found that the photographs were taken in 1927. As the details of Shimizu’s investigation are unknown, both assertions need to be reexamined. First, we confirmed that the aerial photographs that were archived in three different locations were identical, and as such, the assertions of Hattori and Shimizu are conflicting. Then, we analyzed buildings, railways and roads as appearing in the photographs, and determined that the photographs were taken in 1927. Furthermore, we examined the condition of tree canopies and the shades of two buildings, and estimated the period when these aerial photographs were taken. As a result, we concluded that the aerial photographs were taken in 1927 and most likely between late August and early September.