Type name containing slash doesn't work with REST search api

I switched from Java API to REST API. There is an index "derive" with type named "par/chi" containing "/".

curl -XGET 'http://localhost:9200/derive/par/chi/_search?q=heart'

I can encode the "/" to "%2F" to make request valid for elasticsearch server. However, it wouldn't return me any results since the type is "par/chi", not "par%2Fchi".

How can I make it work using the REST API to handle the special type name?

I am using version 2.1