A node description, or simply a node, is a pair of a node identifier and a feature constraint. In queries, node identifiers must be node variables (in the example: #n1):
#n1:[word="das" & pos="ART"]
Please note: The use of constant node identifiers is reserved for corpus definitions only. It may not be used in corpus queries:
(*) "id1":[word="das" & pos="ART"]
In queries, the node variable can be completely omitted from a node description unless it is needed for coreference with some other node description. This means that a plain feature constraint is interpreted as a node description with an unspecified node identifier.
[word="das" & pos="ART"]
On the other hand, a node variable by itself, #n1, is interpreted as an (unspecified) node description, i.e. as #n1:[ ].