Nanhai No. 1 has provided substantial archaeological evidence of a large-scale standardized measuring system that functioned in a regional and temporal framework within a maritime trading system in Southeast Asia. The copper scales and weights from the late 12th-century Southern Song dynasty vessel provide insight into the highly developed measuring standards that supported long distance trade throughout Southeast Asia.
Standardized Weights Used on Nanhai No. 1 Vessel
Some of the largest quantities of metalware discovered on Nanhai No. 1 included copper scales and copper weights for determining the value of precious metals. While these instruments represented more than just simple trade tools, they embodied a standardized system for valuing commodities consistently throughout a multitude of diverse markets and cultural boundaries. The copper weighing equipment was used in conjunction with approximately 2400 grams of gold jewelry (rings, belt accessories, earrings and necklaces), as well as over 300 kilograms of silver ingots, which indicated the continued use of the equipment in the commerce of precious metals.
Regional Evidence of a Standardized System
One of the greatest evidences of a standardized measurement system being used throughout Southeast Asia came from comparing the same time frame of contemporaneous sites. A copper weight from the Saudi Arabian port city of Al-Serrian, which was found in a context dated to the time period of the Nanhai No. 1 shipwreck, had features identical to the copper weights from the Nanhai No. 1 shipwreck. This indicates that both the East and West Asian regions utilized the same scale for transactions involving precious metals during the Song Dynasty. This discovery extended the geographical range of standardized weights from the South China Sea to the Arabian Peninsula, demonstrating that there existed a truly globalized measurement system.
Additional evidence supporting the existence of a regional standardized weight system comes from archaeological discoveries made at major trading centers in Southeast Asia. Identical gold leafs bearing identical designs and stamped markings have been located in regions such as Khao Chai Son in southern Thailand and Kota Cina on the Indonesian island of Sumatra. The consistency of these finds indicate that standardized weights were not simply Chinese imports; rather, they were integrated parts of the regional trading system.
Temporal Continuity and Spatial Extent
It appears that the standardized weight system continued to operate over a number of centuries (the 10th through 13th centuries). Archaeological evidence from multiple shipwrecks found in the South China Sea region demonstrate the continued use of the standardized weight system:
• The Intan shipwreck contained tin ingots, lead ingots, iron objects and gold foil, as well as gold and silver jewelry.
• The Java Sea shipwreck contained numerous metal raw materials and artifacts, including 865 kg of copper ingots, 792 kg of tin ingots and 479 kg of copper alloys.
• The earlier wrecks (10th century) through later wrecks, such as the Nanhai No. 1 (12th century) all demonstrated the continued use of standardized metal trade practices.
Industrial Chain Interdependence
The standardized weight systems were part of a larger industrial supply chain designed to produce and sell metals over a wide area extending from the South China Sea region to West Asia. Research indicates that gold ornaments located at Khao Chai Son, although not as varied as those located at the Nanhai No. 1, shared stylistic and design similarities to other gold ornaments found in India and other areas beyond China, such as West and South Asia. This indicates that the standardized weight systems were capable of facilitating the coordination of production and manufacture in addition to trade. Chinese artisans may have manufactured gold items to be sold in specific regions based upon local demand and style preferences, and in many cases it was impossible to distinguish the workmanship from that of local, Indian or Javanese craftsmen. Therefore, the standardized weights likely enabled cross-culturally coordinated production networks.
Measurement and Currency Standards Integration
In the case of Southeast Asia, the standardized weight system was closely linked to currency standards throughout the region. Research suggests that Southeast Asia adopted a gold and silver standard currency system early in its development to enable international trade by mass, especially due to the influence of the Arab and Indian trade networks. The ability to use identical weighing equipment across such long distances allowed for the creation of a common currency standard.
Archaeological discoveries demonstrate that countries and regions that traded with China, including South Asia and West Asia, have found Chinese coins, as well as used standardized Chinese-style weighing equipment, thus creating a complete system of measurement and exchange.
Implications for Understanding Medieval Commerce Systems
The evidence from Nanhai No. 1 demonstrates that medieval Southeast Asian commerce functioned on a principle of standardization that rivaled modern international commerce. The identical copper weights found in the South China Sea region to Saudi Arabia demonstrate the close trade relations that existed between the Eastern and Western regions of Asia in the trade of precious metals.
The standardization of weights enabled the complex commercial activities associated with the Nanhai No. 1 to serve as a central node in a wider network of commerce, providing seamless service to the needs of stakeholders in the trade.
The archaeological record demonstrates that this was not merely a Chinese export system, but a true regional standard that facilitated the exchange of goods, technology and culture between China and neighboring countries in the South China Sea region, thereby establishing what can be considered one of the earliest international trade protocols based on standardized measurement.
Zhang, Y., Xie, M. and Wang, Y. 2024. Metal trade and contraband: archaeological discoveries and insights from the Nanhai No.1 merchant shipwreck. Journal of Maritime Archaeology 19, 265–289. https://doi.org/10.1007/s11457-024-09400-y.