著者

大澤 正己

出版者

国立歴史民俗博物館

雑誌

国立歴史民俗博物館研究報告 (ISSN:02867400)

巻号頁・発行日

vol.110, pp.89-122, 2004-02

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列島内の縄文時代晩期から弥生時代へかけての初期鉄文化は,中国東北部方面で生産された可能性の高い高温還元間接製鋼法にもとづく可鍛鋳鉄,鋳鉄脱炭鋼,炒鋼の各製品の導入から始まる。また,遺存度の悪い低温還元直接製鋼法の塊錬鉄も希れには発見されるが,点数は少ないのと銹化のためか,その検出度は至って低い。一方,弥生時代の鍛冶技術は,まだ稚拙であって原始鍛冶とも呼ぶべき状況にある。ます廃鉄器(鋳造鉄斧脱炭品破片)の砥石研磨再生から始まり,次に棒(条材),板の半製品を原料とした鏨切り,火炙り成形,砥石研磨による鉄器製作である。鍛冶素材の産地は,弥生時代後期前半頃までは中国側,後期中頃以降は,鉄生産の開始された朝鮮半島側に依存した形跡を残す。本格鍛冶となる羽口使用で,沸し,素延べ,火造りといった工程の開始は古墳時代の前期頃で,鉄鉱石・砂鉄原料の製錬開始は古墳時代中期以降まで待たねばならぬ。朝鮮半島側の製錬の開始は定かでないが,焙焼磁鉄鉱を原料とした石帳里遺跡のA・B区で3~5世紀の操業があり,更に遡るのは確実であろう。これに後続する遺跡として沙村製鉄遺跡が調査された。いずれも円形炉で,列島内の古墳時代後期に属する遺構が広島,岡山の両県でも検出されている。但し,列島内では大口径羽口(送風管)を伴わないので同系とみなすには議論の分かれる事となろう。列島内の円形炉は,砂鉄と鉱石の2通りの原料使用があり,焙焼技術は受継がれている。In Japan the early iron culture from the final phase of the Jomon period to the Yayoi period began at the introduction of iron products of malleable cast iron, iron casting decarbonized steel, and paddling steel with the method of high-temperature reduction which was most likely be adopted in the northeast region of China. Moreover, sponge iron with the method of low-temperature reduction has seldom been found because of hardly been survived; a few specimens and corroded condition cause that they have been found in a very small percentage.On the other hand, the technology of forge of the Yayoi period is still confined in the undeveloped stage and also in the environment which is called a primitive forge. Firstly, the used iron wares (fragments of the decarbonized-casting iron axes) were reused by polishing them with whetstone, and secondly, as the half-finished goods of a stick and a board as raw materials were proceeded to produce iron wares by cutting, taking fabrication of heat, and at the end polishing with whetstone. Raw materials for forge depend on China until the middle of the Late Yayoi period, but after the middle of the Late Yayoi period there is evidence that they depend on the Korean Peninsula where iron production already started.Adopting the funnel which serves as a full-scale forge; pounding, shaping, and refining, these procedures began around the first half of the Kofun period, and the beginning of refinement of iron ore and iron sand should wait until the middle of Kofun period. It is not certain when the refinement adopted in the Korean Peninsula began, however, there are some evidences that heated magnetites as raw materials were used in the A and B areas of Sǒkjang-ri Site in the 3th through 5th century, and it is sure that the date will be much earlier. As the successive site, Sachon Iron Mill Site has been excavated; the remains of furnace are round in plan, and this type has been discovered in Hiroshima and Okayama prefectures, which is belonging to the Late Kofun period. However, any large funnels in diameter have not been unearthed in Japan, therefore, there are some arguments whether or not two specimens are similar in type. As to the round furnace in Japan, iron sand and iron ore were adopted simultaneously for raw materials, and adopting the heating method have been inherited.