Move on board to a fortified place (6)
I believe the answer is:
castle
'fortified place' is the definition.
'castle' can be an answer for 'place' (I have seen 'secure place' mean 'castle' so perhaps 'place' could also mean 'castle'). I am not certain of the 'fortified' bit.
'move on board' is the wordplay.
'move' becomes 'cast' (casting is a kind of moving).
'on board' becomes 'le' (I can't explain this - if you can you should believe this answer much more).
'cast'+'le'='CASTLE'
'to a' acts as a link.
Can you help me to learn more?
(Other definitions for castle that I've seen before include "Stronghold - rook" , "Lincoln, Ludlow or Leeds" , "Move rook and king in the same turn" , "E.g. Harlech, Beaumaris, Windsor" , "Stately home in Yorkshire" .)