tsuyoshi yamaguchi yamaguchi tsuyoshi born october 3 1954 is a japanese politician of the democratic party of japan a member of the house of representatives in the diet national legislature a native of aioi hygo and 1978 graduate of the faculty of law at the university of tokyo he joined the ministry of foreign affairs in 1979 and received a phd from sais at the johns hopkins university in the united states while an attache to the embassy of japan in washington dc yamaguchi served in several bureaus of the ministry of foreign affairs mofa in tokyo as well as the japan defense agency during the period 1982 to 1989 between 1989 and 1995 he held three positions as first secretaryin the embassies of japan in china pakistan and the united kingdom respectively in october 1995 he resigned from the ministry of foreign affairsyamaguchi was elected to the house of representatives for the first time in 2000 he was reelected in 2005 and again in 2009 in september 2011 he became parliamentary senior viceminister for foreign affairs a member of the noda cabinet he studied for his masters degree at sais in washington dc beginning in the fall of 1980 through the spring of 1982 and completed his doctoral dissertation and received his phd thereafter his phd adviser was nathaniel b thayer yasuhiro nakasone professor and senior adviser to the reischauer center at sais a strong interest of yamaguchis that figured prominently in his masters thesis and doctoral dissertation was the evolution of usjapanese relations in the modern era the dissertation is titled the making of an alliance japans alliance policy 19451952 yamaguchi is an only child who was raised by his fathera dentistand his fathers sister he excelled as a tennis star in his student years and has been avid player since he also enjoys skiing when living in the us he took up golf years prior to pursuing his political ambitions yamaguchi took a keen interest in politics and dreamed of serving his country as an elected official he was an ardent admirer of ronald reagan who was serving as us president during yamaguchis student years in washington dc yamaguchi is married and has two daughters