Dong Dau

Archaeology finds

Much at Dong Dau is identical to the layer below: the same axes, the same adzes, the same stone bracelets, pottery of the same shapes. But one thing is entirely new — here many complete bronze tools were found, and stone moulds for casting along with them: rectangular axes, spearheads, fish hooks. A casting mould means bronze casting was no longer a matter of chance; it had become a craft, with people who knew how to do it, doing it over and over to the same pattern. The pottery changed too: no longer thin, light and burnished as before, but thicker and heavier, decorated with comb-incised patterns, waves, spirals, plaited cord.¹

The dating of this layer was measured by radiocarbon and published in 1980: Dong Dau about 3,330 years before present, Trang Kenh about 3,405, both with a margin of plus or minus 100 years. These are the raw figures of that time, uncalibrated by the methods used today, and so are to be read as an approximate range rather than a fixed marker. Set between the Phung Nguyen layer below and the Go Mun layer above, the three line up into one continuous sequence: smelting known but no objects made, objects made and casting moulds in hand, then bronze crowding stone out — with no break anywhere that would force us to assume a party of strangers arrived carrying the technique from somewhere else.¹

The ninety-year survey sets Dong Dau within two further lines of development. In alloying: since Phung Nguyen times people knew how to alloy copper with tin, by Dong Dau and Go Mun casters were adding arsenic and antimony to make arrowheads sharper, and lead came only with Dong Son. In rice: charred rice grains have been found at Dong Dau, which is to say traces of rice cultivation appear earlier than Dong Son, and by Dong Son they are far denser.²