This paper aims to clarify the social activities by the foreign people of Karuizawa in the summer of 1930. First, we investigate several archival data of the years 1911, 1919, 1930 and 1939 in order to situate the summer retreat area in Karuizawa around the year 1930. Through the investigation of these data, we would be able to find out that, while substantial number of villas owned by forigners have been existed, the ones owned by Japanese have increased rapidly and have started to mixed together. Second, by the analysis on the correspondent articles of the newspaper, The Japan Times, in the summer of 1930, we could understand that their summer activities having been started from a series of Chirstian missionaries meetings and the annual meeting of the Federation of Chiristian Missions, that were followed by the Karuizawa Summer Residents' Accociation tennis tournament, its community concerts, and ended with farewell social gatherings. In addition, all of these activities seems to be well structured in order to entertain both foreign and Japanese occupants.
