This article aims at reexaminating the so-called expansionist perception of the world seen in Sat? Nobuhir?(佐藤信淵, 1769~1850)’s works, supproting Park Hun’s criticism against the previous studies of the field and borrowing his categorization of the perceptions into the perception of the world at war and the expansionist perception of the world. The first part of this article is devoted to examining Sat?’s Kond? Hisaku (A Secret Strategy of Expansion, 1823), and the nativist influence on the work being represented in Sat?’s Tenjuki which is a derivation of Hirata Atsutane’s Tama no Mahashira . Succeeding part can be said a new addition to the field. This part examines Sat?’s other works which expresses different version of his view, that is, the perception of the world at war. Three works of Sat?’s are cited and examined here; Seiy? Rekkoku Ryakushi (Compact History of the Western Powers ), B?kaisaku (Strategy of Defending Seacoast ), and Sonkazatekiron (Argument on Supporting China to Dispel the Western Barbarians ). Even though they shows slight differences to each other, especially on the issues concerning China, they share common attitude of treating China as Japan’s foremost partner or the most important barrier against the West in the world at constant war. Being ciritcally different the perception of the world and China in 1823, this view of the world at war and appraisement of China’s status should be said Sat?’s basic and consistent position. This conclusion would mean that the view expressed in 1823 was a mere happening instigated by nativism. Examination of Sat?’s passion for saving people done in the final part, however, shows that the view of 1823 was a sort of messianism, a belief that the Prince could save the world as well as Japan and would give his people peaceful and prosperous life.