本文嘗試重建宋元明三代福建沿海居民透過實地觀測所得有關臺灣的地方知識，藉以釐清古代中國人對臺灣的認識。宋人記載從澎湖與福州外海望見流求，明人記載從福卅鼓山望見琉球。此等記載常被史家視為無稽傳說而未深究。但今人觀測記錄與照片已確認，從澎湖可在極晴之日望見臺灣群山連綿成一體。現代測量學亦指出，福建中北部沿海可在極睛之日望見臺灣高山之巔。宋代以來澎湖與福建中北部沿海多處望見流求的長期記錄，與現代觀測知識相加，使我們可確認宋元福建人對他們稱為流求、琉球的臺灣有相當清楚的地方知識。明初臺灣被明廷改稱小琉球，明清福建方志裡望見流求的記載逐漸改為望見琉球，再改為小琉球。可回推宋代望見流求的紀錄屬實，以及明代之小琉球確是宋元之流求、琉球。更有甚者，臺灣高山連綿全島成一體，長年在臺灣海峽活動的福建海員不時望見，必然知道臺灣是一個大島，而非數個小島。然而，傳統農業社會文字使用不普及， 傳播不便，士人與農漁之間階級界線分明，且直到明末臺灣在政治經濟上對中國毫無影響而不受重視。因此，福建沿海居民有關臺灣的地方知識並不易傳入朝廷與文人的主流文化裡。這主流文化與地方知識的差距表現在史書有關流求、琉球的記載稀少、含糊，甚至錯誤。

Based on the records of sighting Liuqiu in the Song and Ming Dynasties, this paper attempts to reconstruct the Fujian coastal inhabitants' knowledge of Taiwan in order to clarify ancient Chinese knowledge concerning Taiwan. There are Song records about sighting Liuqiu from Penghu and Ming records about sighting Liuqiu from Gu Mountain of Fuzhou. Historians view such reports as unfounded legends and do not bother to investigate them. Yet contemporary photos show Taiwan indeed can be seen from Penghu, while modern geodesy indicates the possibility of seeing the peaks of Taiwan mountains from the central-n01ihem coast of Fujian and from Gu Mountain when the air is unusually clear. These ancient reports of sighting Liuqiu, supported by contemporary photos and geodesy, allow us to infer that Fujianese during the Song, Yuan, and Ming Dynasties actually possessed substantial knowledge of Taiwan. Taiwan was renamed Little Liuqiu in the early Ming. Indeed, the Ming-Qing Fujianese gazetteers changed their reports of sighting Liuqiu (流求) to Liuqiu (琉球), and then to sighting Little Liuqiu. These changes confirm the Song sighting reports, and indicate that what the Ming called Little Liuqiu was indeed what the Song called Liuqiu . Furthermore, the high mountain range that lUns through Taiwan must have led ancient Fujian seamen who sighted it to understand that Taiwan was a large island rather than several small islands. However, low literacy rate s, social barriers between peasants-seamen and intellectuals in traditional China, and the politico-economical insignificance of Taiwan until the late Ming all prevented Fujianese local knowledge about Taiwan from being absorbed into the official knowledge of the imperial court and mandarins. This gap between local knowledge and official knowledge led to the sparsity and inaccuracy of historical records concerning Liuqiu (流求) and Liuqiu (琉球).