域外漢史料的研究，可以為探究中國東部區域社會提供富有價值的線索。本文通過對江戶時代日本翻譯家岡島冠山小說中的一個情節之解析，指出：此情節演自福建，特別是福州府「契兄契弟」之畸俗，它源於明清時代當地海外貿易背景下的人際契約關係，但又因海外貿易的生活實況而發生變態，並由此對明清時代的「南風」北漸及日本社會，都產生了不同程度的影響。從中，我們可以看出跨文化傳播中民俗的傳承與變異。

　　　　　The study of overseas Chinese literature often provides valuable clues to the understanding of local societies in eastern China. This paper analyzes the plot of a novel by the Japanese translator Kanzan Okajima 岡島冠山 of the Edo Period, and proposes that the plot is based on the male homosexual practices prevalent at the time in Fujian, and particularly in Fuzhou Prefecture. Male homosexuality in Fujian arose from the social relationships that developed against the background of overseas trade, and underwent a transformation during the Ming and Qing dynasties. As the influence of southern China increased, it spread to northern China and even as far as Japan. The author hopes to shed light on the transmission and transformation of folk customs through the process of cultural exchange.