<論説>朱思本の輿地図について

Abstract

今は失われた元代の代表的地図としての朱思本の輿地図を、明の羅洪先の「広輿図」に基づいて復原しようとするのが本稿である。広輿図は縮者自身言明するように、図形の正確な朱思本図を分割し改訂増補したものである。従ってそれが収載する諸図を吟味し、そこに含まれる非朱思本図的要素を逐次排除してゆくならば、原図である朱思本図の相貌はおのずと浮び上ってくる筈である。このような過程を踏んで明らかにし得た事柄は、先ずその方格が毎方百里のものであったろうということである。そして羅洪先の見た朱思本図に関する限りにおいて、その縮尺は八分百里であつたと考えられる。図は朱思本が言う如く、外国地方を描かず、同時代の「声教広被図」の如き世界図ではなかった。図形や作図法にイスラム地図学の影響を受けないばかりか、沿革に執着する伝統的な中国地図学を忠突に継承するものであった。そしてこの図の大きな特色と考えられるのは、元の都実の探検によって明らかとなった黄河河源地方の地理を、正しく中国全図の中に位躍づけた点であったろう。

Chu Ssu-pên's 朱思本 Yü-ti-t'u (輿地図, Terrestrial Map), one of the representative maps brought out under the Yüan Dynasty, is no longer extant but survived by the Kuang-yü-t'u (広輿図 Enlarged Terrestrial Atlas), an atlas in which Lo Hung-hsien 羅洪先 under the Ming Dynasty divided, enlarged and revised the original map. An attempt, therefore, was made by the author of this paper to reconstruct Chu Ssu-pên's map on the basis of this atlas and the resultant findings are here reported. 1) The scale of the grid of this map was 100 li 里 to the division. So far as the copy of Chu Ssu-pên's map to which Lo Hunghsien referred was concerned, its reduced scale, therefore, was 8 fên 分 to 100 li or 1 : 2, 250, 000. 2) The map mainly represented China proper, including the western half of Korea on the east, the western boundary of Yun-nan 雲南 province on the west, the northern half of An-nam 安南 and the Island of Hai-nan 海南 on the south, and the northern part (stretching outward about 600 li according to the then standard measure) of Kharakhorum 和寧 on the north. Viewed from the grid of 100 li to the division, there were 91-92 divisions from east to west and 89-90 divisions from south to north. 3) The map was under no influence of Islamic cartography in point of its figure and map-making method but based upon the traditional principles of Chinese cartography, with the characters of historical maps fully realized. 4) By Chu Ssu-pên's map, the riverhead and upper reaches of the Huang Ho (Yellow River) discovered as a result of Tu Shih's 都実 expedition in A. D. 1280 was represented on the general map of China for the first time. The Chu Ssu-pên's Ho-yüan-chi (河源記, Record of the Source of the Yellow River), was a laborious work written by him with this in view