Southeast Asia is a clear example of how new techniques (both of power and production) and products “generate new social forms” (Higham 2002: 291). In Vietnam, Yunnan, and Thailand, the development first of bronze, and later iron metallurgy, led to exchanges and migrations, and fostered the intensification of agriculture as well as the emergence of powerful chiefdoms; the attendant process of militarization can be seen from the large amount of weapons recovered. Bronze working began in northern Vietnam, northeastern Thailand, and central Thailand as early as the second millennium bce.