The purpose of this paper is to clarify the trade activity of the ancestors of the indigenous peoples of the Lower Amur Basin in the 18th and 19th centuries and to reexamine the discourse of their society and culture in classical ethnography. They have usually been described as hunters, fishermen, or collectors of wild plants in much ethnography since the late 19th century, and the primitiveness of their foraging life style, fishing and hunting techniques, and social structure has often been underlined by anthropologists, ethnologists, and historians. The policies of the former Soviet Union to rescue them from the poverty caused by their primitive level of production was based on such discourse of the scholars. However, were they really poor? Were their life style, culture, and society really primitive? Historical documents written by Japanese explorers and investigators in the 18th and 19th centuries, Mogami Tokunai, Mamiya Rinzo, Nakamura Koichiro, and so on, indicate that they had a highly sophisticated culture and a complex society. For example, modern ethnologists often underline the fact that the peoples of the Lower Amur were ichthyophagi, and that a piece of dried fish occupied the same position as a piece of bread in European meals. On the contrary, Japanese investigators said that their staple food was a cup of boiled millet, usually put in a small bowl of china or lacquer ware. Though ethnologists often described fish skin coats in detail, most of their clothes were made of cotton, and their ritual costumes were even made of silk. It is a fact that millet, cotton, silk, china, and lacquer ware were not their original products, but Chinese or Japanese ones which they obtained through trade with Chinese and Japanese. It is also a fact, however, that these things occupied an important position in their cultural complex. It is an injustice for researchers not to properly evaluate them and not to pay any attention to the trade activity. The trade activity of the ancestors of the peoples of the Lower Amur in the 18th and 19th centuries was called "Santan trade" by Japanese investigators of the same centuries. "Santan" was an ethnonym of the people of the Lower Amur, which had often been used as a name of the ancestors of the indigenous people of this region as a whole. It was Mamiya Rinzo who clarified who the Santan people were. In his investigation in 1809 and 1810 he found out that the Santan lived between the villages of "Uruge" (bIppH, later Russian village "MaxcrM Tojm cHA") and "Poru" Mon, later Ul'chi village "LlepxbIti Ap") , that they called themselves "Mango" (this is the same self denotation as "Mangguni") , and that their neighbors upstream along the river were called "Korudekke" (Goldok) and those downstream were called "Sumerenkuru". The range of habitation, the self denotation "Mango", and the linguistic materials indicate that the Santan people were ancestors of the Tungus-speaking peoples of the Lower Amur today, especially the Ul'chi (Olcha) and a part of the lower Nanai (Goldi) . The Santan trade has long been studied as a theme of historical studies of Northern Japan. However, though many facts have been clarified from the historical point of view, historians have long overlooked an important one namely that it was trade that kept the levels of life and culture of the peoples of the Lower Amur and Sakhalin in the 18th and 19th centuries higher than those described in ethnography. This is because the historians could not evaluate the function and role of trade activity in the society and culture of the indigenous peoples, because their point of view was usually set not on the side of the indigenous traders, but on that of authors or editors of literary sources, who were often government bureaucrats. This paper is one of my experiments, in which I try to describe the historical events of the peoples of the Lower Amur and Sakhalin such as the Santan trade from the point of view of those who were describe