Introduction 9
speaking, these locales are widely referred to as nodes, or points of relative
condensation and significance. As a working hypothesis the present research
agenda distinguishes in the main between two types of nodes (although other
types may be added), namely major or primary and minor or secondary nodes,
as follows. A primary node is a major cultural centre,12 a location where knowl-
edge and cultural techniques of any kind are being produced and diffused.
As such it creates, absorbs and conveys the spread of knowledge in a given
region. In referring to a major node, i.e. when defining its relative importance
in a given network, one may speak of a locale where cultural densification
(German: Verdichtung) on a high scale occurs. In geographical terms major
nodes are located along primary travel routes, often at important strategic
junctions or intersections.
A secondary node is a minor cultural centre or habitation, which primarily
serves as a conductor for cultural practices that have for the most part been
produced elsewhere. A characteristic of both types of nodes is that they belong
to a network often passing through or transversing several culture zones, as
indeed is the case with the network of routes across the area dealt with in this
volume, namely along the oasis towns located at the rim of the Tarim basin, the
Tibetan and Transhimalayan regions.
In order to ascertain what features might dynamically generate central-
ity on networks, directionality between locales plays a crucial role. Important
sites or major nodes may push their influence, knowledge, ideas, technologies,
religious ritual systems, pantheons etc. toward their neighbours’ boundaries;
equally, the very same nodes might be a source of attraction for the same or
further neighbours, pulling in other information or material objects.
Beyond such pull and push factors describing the degree of general inflow
and outflow of major nodes, Ray Rivers, Carl Knappett, and Tim Evans, apply a
network approach in archaeology to further differentiate between two types of
centrality of a ‘busy’ site (or major node): namely a ‘central place’ or ‘hub’ and a
‘gateway’. Hubs, according to the authors, are “not necessarily the busiest sites
of a network as a whole, [.. .] but [.. .] those [that] are relatively the busiest
within a region or neighbourhood.”13 On the other hand, a gateway is described
as a site of high betweenness centrality and
12 Some authors in this volume use the term ‘hub’ rather than node, as it was introduced
during the above-mentioned workshop (see acknowledgements). See also the further
definition of the term ‘hub’ below in the text.
13 Rivers, Knappett, and Evans, “What Makes a Site Important?,” 129.