花東縱谷北段玉製錛鑿形器工藝技術探析──以豐坪村遺址為例

Investigating and Analyzing the Craftsmanship in Producing Nephrite Adze-Chisels Unearthed in the Northern Section of the East Rift Valley: A Case Study on the Fengpingtsun Site

豐坪村遺址位於花東縱谷北段的平原上，為繼平林、重光遺址之後，第三處於玉礦產區附近發現的玉器作坊遺址。為了釐清豐坪村遺址的內涵，筆者於二○一三年進行發掘，確認豐坪村遺址為一處史前遺址，且為首次發現於花東縱谷北段平原地區之遺址，此遺址的發現意味著當時平原地區已適合人類居住或活動。此次發掘在豐坪村遺址出土密集的打剝和切鋸玉廢片、閃玉製錛鑿形器半成品、打剝片岩堆等，可見錛鑿形器製作過程中各個階段的遺留，屬於小型的錛鑿形器玉器作坊遺址，對進一步釐清新石器時代中期製玉工藝的內涵具有積極的意義。

Sitting on the plain in the northern section of the East Rift Valley, the Fengpingtsun Site is the third site (following the Pinglin Site and the Chungkuang Site) where nephrite tool workshops were discovered around nephrite-producing areas. To clarify the nature of the Fengpingtsun Site, the author conducted an excavation at the Fengpingtsun Site in 2013 to ensure that it is prehistoric and is the first site discovered in the northern section of the East Rift Valley. The discovery of the site suggests that the plain was already suitable for human habitation and activities back then. More importantly, the emergence of the Fengpingtsun Site challenges deeply-rooted ideas that the plain of the Rift Valley holds no prehistoric sites, warranting further archeological investigations into the area. The chipped sawn nephrite scraps, half-finished nephrite adze-chisels, and chipped schist piles unearthed in substantial amounts at the Fengpingtsun Site correspond to the different stages of adze-chisel production, further clarifying the nature of nephrite craftsmanship during the Mid-Neolithic Period. The procedures for producing nephrite adze-chisels applied at the Fengpingtsun can be roughly categorized as follows: (1) There are two ways to source rough nephrite. Most people directly head for nephrite-producing areas around Laonao Mountain, while few fetch along rivers near nephrite-producing areas such as Shoufeng River, Paipao River, and Lao River. Either way, qualified rough nephrite were supposedly singled out on-site before being transported to the sites for further processing. (2) Directly chip rough nephrite into a piece around 10~10+ cm. There are two processing methods: a. Beat and grind it into hoe-axes or adze-chisels to produce a single item. b. Perform vertical and horizontal straight cut to produce multiple pieces of nephrite chisel. (3) Directly saw rough nephrite multiple times into flat nephrite materials with squared-angles. Afterwards, saw and grind them into many pieces of adze-chisels. This production method is commonly seen at the Takeng culture in Hualien, the Shuntanpu culture in northern Taiwan, and the Niumatou culture in central Taiwan. In addition, sawn flat nephrite materials, adze-chisels, and their half-finished products are frequently unearthed at the above-mentioned sites. The author speculates that those sawn flat nephrite materials may be transported to the sites from nephrite-producing areas before being processed. Furthermore, during this period, such nephrite materials, alongside other types of nephrite materials, were frequently used for further processing at many sites, as evidenced by the unearthing of adze-chisels and half-finished adze-chisels. The same can be seen at the Chungkuang Site, the Fengpingtsun Site, and the Pinglin Site. Therefore, it can be inferred that the main purpose for producing these types of sawn flat nephrite was to prepare materials for crafting adze-chisels, after which multiple pieces of adze-chisel could be produced within a short period of time by simple straight-cut, sawing, and grinding, setting the scene for mass production and quality manufacturing.