<論説>古墳時代馬具における繫 (がい) の基礎的研究

Abstract

本稿では古墳時代の轡や杏葉、雲珠や辻金具などを連結し、馬装として機能させるうえで重要な繫とよばれる有機質製ストラップについて基礎的整理をおこなった。これまで繫についての認識が不十分だったため、馬具研究の俎上にあげられることはほとんどなかった。本稿では古墳出土の金属製馬具に残された繫の観察に基づいて、構造や装飾技法の点から分類をおこなった。ついで、どのような馬具のセットに各種類の繫が確認できるか検討をおこない、連結された鏡板轡や杏葉などの金属製馬具の編年に基づいて繫の時間的消長について検討した。また、鏡板轡や杏葉の系列と、連結された繫の種類との間に相関があるかどうかを検討し、繫の消長が鏡板轡や杏葉などの金属製馬具の消長とも連動していることを明らかにした。繫は古墳時代馬具の変化、系譜問題、舶載と模倣のプロセス、生産流通体制の変化を明らかにするうえで重要な馬具の一つである。

During the Kofun period, a culture of horse riding was adopted by elites. We can recognize this phenomenon from horse trappings found in kofun burial mounds; however, we can find only fragments of such horse trappings due to corrosion. Horse trappings comprise fragments of cheek bits, strap unions, saddles, stirrups, crupper strap unions, and pendants. If we equip a horse with these parts, we must join them with many straps. These straps, known as gai 繋, are important in equipping a horse with various horse-related ornaments. However, in many excavations that found traces of horse trappings, corrosion and deterioration have left such straps barely recognizable. In recent years, archaeological observations have paid increasing attention to these little pieces of evidence that comprise metal parts, and we can now find clues that allow us to reconstruct both the techniques and materials that were used for horse straps during the Kofun period. However, such studies are sparse and few at present. This paper establishes a chronology and a means for the classification of horse straps. First, I examined the techniques and materials that were used for making horse straps. By examining many cheek plates, strap unions, crupper strap unions, and pendants, I was able to classify the two basic techniques used for making horse straps. One was through a double layering technique, and the other was through braiding. In the case of double layering, many supplemental decorative techniques were used such as, textile wrapping, rim decoration with stiches, supplementary stitching, wrappings with unidentified materials, and the attaching of decorated strings. Second, I classified the horse straps into 12 types by identifying different techniques and materials used. I further classified the double layering technique into nine types: normal, textile core, stitched, textile wrapped, stitched and textile wrapped, leather stitched strings, braided stitched strings, straps wrapped with unknown material, and those with decorative strings attached. Next, I classified the braiding of straps into two types: two-ribbed braided straps and four-ribbed braided straps. Third, I examined these various types of horse straps and identified which types of trappings they were joined to. This included cheek plates, strap unions, crupper strap unions, and pendants. The normal type was used from the 5th stage of the Middle Kofun period to the 1st stage of the Final Kofun period. It was found that they were joined to many types of cheek plates or pendants. For example, they were attached to f-shaped cheek plates, sword-shaped pendants, bells with pendants, palmette and phoenix-motif, heart-shaped cheek plates and pendants, and simple circular iron cheek plates. The stitched type was confirmed in three locations, such as the Kami- Enyatsukiyama Kofun 上塩冶築山古墳A. The textile-wrapped type was also confirmed in three locations, such as Bakuya Kofun 牧野古墳A. Stitched and textile-wrapped types were, however, confirmed in many locations. These were used from 7th stage of the Mjddle to 3rd stage of the Late Kofun period, and they were joined to f-shaped cheek plates, sword-shaped pendants, cross-motif oval cheek plates, three-leaf oval pendants, bell-shaped cheek plates, and bell-shaped pendants. Leather-stitched strings were confirmed in three locations, such as Takehara Kofun 竹原古墳b. Braided-stitched strings types were confirmed on only in Fujinoki Kofun 藤ノ木古墳A. Meanwhile, string-wrapped with an unidentified material type was confirmed in Takehara Kofun 竹原古墳a. Decorative string-attachment types were confirmed in Tamakiyama No.3 tumulus 珠城山3号墳 etc. This type was used during the 3rd and 4th stages of the Late Kofun period. On the other hand, two-ribbed braided straps were confirmed in many locations. For example, in the case of Kamo-inariyama Kofun 鴨稲荷山古墳, it is possible to recognize cross-motif oval cheek plates and three-leaf oval pendants. In other cases such as that of Ipponmatsu No.1 tumulus 一本松1号墳, the straps were joined to phoenix motif heart-shaped cheek plates and pendants. The two-ribbed braided strap was used from the 7th stage of the Middle until the 4th stage of the Late4 Kofun period. Four-ribbed braided straps were confirmed in two locations, Kinreizuka Kofun 金鈴塚古墳B, and Shimo-lshibashi Atagozuka Kofun 下石橋愛宕塚古墳a. In both cases, four-ribbed braided straps were connected to flower-shaped cheek plates and pendants. Both cases belong to the 4th stage of the Late Kofun period. Fourth, I examined the use of horse straps based on the result of these analyses. By engaging in such examinations, I suggested that the three main types of cheek plates and pendants, f-shaped cheek plates, sword-shaped pendants, cross-motif oval cheek plates, three-leaf oval pendants, bell-shaped cheek plates, and bell-shaped pendants, tended to be joined by stitched and textile wrapped straps. Various cheek plates and pendants, which were adopted from the 3rd stage of the Late Kofun period, tended to be joined by many types of straps. I therefore concluded that the change in strap types, which were used to join cheek plates and pendants, was linked to changes in many other metal parts such as cheek bits, strap unions, crupper strap unions, and pendants. Furthermore, I concluded that the historical background of this change involved three causes: 1) the changes in the systems of horse trapping production and distribution, 2) the mixture with many new types of imported parts, and 3) the changes in the symbolic systems supported by decorated horse trappings.