one group by another was only one way of mutual cultural penetration. In
other cases, a group which occupied the higher altitudes and practised
hunting or slash-and-burn agriculture came into closer contacts with
another group in the valleys which practised some form of higher
agriculture; frequently, such contacts resulted in particular forms of
division of labour in a unified and often stratified new form of
society. Recent and present developments in South-East Asia present a
number of examples for such changes. Increase of population is certainly
one of the most important elements which lead to these developments. The
result, as a rule, was a stratified society being made up of at least
one privileged and one ruled stratum. Thus there came into existence
around 2000 B.C. some new cultures, which are well known
archaeologically. The most important of these are the Yang-shao culture
in the west and the Lung-shan culture in the east. Our knowledge of both
these cultures is of quite recent date and there are many enigmas still
to be cleared up.

[Illustration: Map 1. Regions of the principal local cultures in
prehistoric times. _Local cultures of minor importance have not been
shown._]

The _Yang-shao culture_ takes its name from a prehistoric settlement in
the west of the present province of Honan, where Swedish investigators
discovered it. Typical of this culture is its wonderfully fine pottery,
apparently used as gifts to the dead. It is painted in three colours,
white, red, and black. The patterns are all stylized, designs copied
from nature being rare. We are now able to divide this painted pottery
into several sub-types of specific distribution, and we know that this
style existed from _c_. 2200 B.C. on. In general, it tends to disappear
as does painted pottery in other parts of the world with the beginning