Confused about search/count queries

Elastic Stack Elasticsearch
1

I am taking ES training in NY later this month, but I sort of need to know this before then.

I have index 'asset', of type 'ip'. Running ES 0.19.10

The query:

curl -XGET 'http://localhost:9200/asset/ip/_search' -d '{"query":{"query_string":{"query":"continent:EU"}}}'

works fine but if instead of _search I use _count, it gives me an exception.

"QueryParsingException[[asset] No query registered for [query]]"

If I change the request body, however, to:

 '{"query_string":{"query":"continent:EU"}}'

_count works.

What am I missing?