The importance of connection among Japan, China, and Russia was his passionate political belief, about which he told Hirobumi ITO just before his assassination, and it is considered that he tried to make approach to discuss the ideas of the mandatory administration of Manchuria or the foundation of a buffer state there, behind the scenes of the plan of the cabinet of Giichi Tanaka to establish the Department of Overseas Affairs.
日中露の結合関係の重要性は新平が暗殺直前の伊藤にも熱く語った信念であり、田中義一内閣が拓務省設置構想の背後で構想した満洲委任統治構想、もしくは満洲における緩衝国家設立を打診せんとしたものとも指摘される。