Expert in pieces? (11)
I believe the answer is:
grandmaster
'expert in pieces?' is the definition.
The definition suggests a singular noun which matches the answer.
'expert in' is the wordplay.
I cannot really understand how this works, but
'expert' could be 'master' (master is a kind of expert) and 'master' is found in the answer.
The remaining letters 'grand' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for grandmaster that I've seen before include "Chess player of the highest class" , "Star chess player" , "A top chess player" , "Exceptional player" , "Senior chess player - senior mason" .)