江戸時代の草摺に用いられた小札の鋼板製作方法

摘要

日本において鎧は，出土遺物や埴輪の装飾などの美術工芸品に見られるように，古墳時代にはすでに使用され，長い歴史を持つ.その中で日本の鎧の形式は，各時代の戦闘法を反映して変化している.鎧の形式に関する研究を参考に変遷を迎ると，日本の鎧は古墳時代の短甲(たんこう)ゃ挂甲(けいこう)に始まり，平安時代後期から鎌倉時代には騎馬戦に対応した大鎧となる.また，歩兵戦が主流となり，室町時代末期から江戸時代にかけ火縄銃が導入されると，日本刀，弓矢，火縄銃に対応した防御性の高いとされる当世具足が主流となる.江戸時代初期，島原の乱以降，武断政治から文治政治に変わると，鎧は装飾性を重視したものや大鎧を模した復古調が現れる.その後，幕末の混乱とともに需要は一時的に高まるが，明治時代に入るとともに鎧は終焉の時を迎える.%The manufacturing technique of steel sheets in the Edo period has been investigated from a Kusazuri armature that is a protector of the waist. The size of the steel sheets is 300 mm by 235-265 mm and 0.6-1.0 mm in thickness. Most of the steel sheets are composed of multiple steels with different carbon contents. The nonmetallic inclusions in the steel sheets are FeO and a few 2FeO-SiO_2. Most of the nonmetallic inclusions are finely distributed in the sheets while some lie in lines in parallel to the sheet surface. The nonmetallic inclusions which are arranged in lines were produced during forge welding. From the number of lines, forge welding was performed one to three times. The nonmetallic inclusions are elongated in the side direction of the sheet than the longitudinal direction. This means that a large plate was extended while maintaining the width of 300 mm and was cut to the length of 235-265 mm. The Vickers hardness of the sheets was larger than that of annealed steel sheet in the literature, suggesting that annealing was not performed to the steel sheets after forging. Finally, the steel sheets were shaped and curved slightly.