Takahiro Kawai studies algebraic analysis; to be more specific, first, microlocal analysis of linear differential equations and the S-matrix, including infrared singularities, and, second, exact WKB analysis of linear differential equations and non-linear differential equations. He is currently most interested in the interplay of microlocal analysis and the exact WKB analysis; his expectation is that a central role will be played in the exact WKB analysis by the notion of a virtual turning point, which had been introduced in his joint work with T. Aoki (Kinki Univ.) and Y. Takei (RIMS) through the microlocal study of singularities of Borel transformed WKB solutions.