He advocated the historical science methodology, which modeled its methodology for the Qing-style study of old documents, and based on this, he denied the existence of Takanori KOJIMA (a personage appears in "Taiheiki" story) as a real figure as well as the anecdotes related to Masashige KUSUNOKI, and thus, he was dubbed 'the doctor elimination.'
清考証学派に範をとる歴史学方法論を主張、これに基づき児島高徳の実在や楠木正成の逸話を否定し「抹殺博士」の異名をとった。