Some researchers believe that the image of the golden country of Jipang, which is mentioned in "The Travels of Marco Polo," was brought about through trade with the Asian continent through the port of Tosaminato by the Oshu-Fujiwara clan (later the Ando clan).
マルコ・ポーロの東方見聞録に登場する黄金の国ジパングのイメージは、奥州藤原氏（後に安東氏）による十三湊大陸貿易によってもたらされたと考える研究者もいる。