Investigating macroscopic transitions in Japanese foreign policy using quantitative text analysis†

摘要

This study introduces new quantitative text analysis methods into foreign policy analysis. Quantitative text analysis in the social sciences is currently aimed in two directions, namely (a) more systematic analysis using larger amounts of data sets and (b) more detailed analysis using linguistic knowledge. Our methods, by using recent techniques in natural language processing, integrate these two different trends, and achieve more systematic but detailed analysis. We apply our methods to 147 Diet speeches of Japanese prime ministers, and shed new light on the character of Japanese foreign policy. This study makes a methodological contribution to foreign policy analysis and a substantial contribution to the study of Japanese foreign policy.