Bishop in file at the back by a rook getting check (6)
I believe the answer is:
exarch
'bishop' is the definition.
(thesaurus)
'file at the back by a rook getting check' is the wordplay.
'at the back' indicates one should take the final letters.
'by a' becomes 'xa' (I can't justify this - if you can you should believe this answer much more).
'rook' becomes 'r' (abbreviation in chess).
'getting' means one lot of letters go next to another.
'check' becomes 'ch' (I've seen this in other clues).
The final letter of 'file' is 'e'.
'e'+'xa'+'r'+'ch'='EXARCH'
'in' is the link.
Can you help me to learn more?
(Another definition for exarch that I've seen is " Bishop".)