Solidification simulation of the Anyang niuzun: Insights into late Shang Dynasty bronze casting techniques

Abstract

Ritual vessels of the Bronze Age in China, are numerous and their exquisite craftsmanship offers a means to understand ancient Chinese society. Important bronzes have been unearthed at the site of Yin, the late Shang dynasty capital city, in present-day Anyang. One particularly significant example discovered in the Yin ruins is a cattle-shaped wine vessel (niuzun). This study combines archaeological observations and solidification simulation methodology to investigate the casting technologies used to produce this vessel and to evaluate bronze craftsmanship at the Yin capital city during the Late Shang Dynasty. By reconstituting the process of the vessel's dynamic solidification, it was found that the niuzun's features have an even wall thickness design, use metal chaplets, and incorporate bronze patches. In addition, the artisan's deliberate sprue placement significantly reduced casting defects. These findings indicate that by the late Shang Dynasty, artisans had already mastered piece-mould casting techniques, and that for the exquisite bronze niuzun, they designed an impeccable mould conforming to extremely high casting standards. This study provides a novel perspective on understanding ancient metalwork technology considering transient solidification processes, and offers valuable insights for studying other metal relics.