The mating game? (5)
'the mating game?' is the definition.
(as in checkmate)
This is the entire clue.
(Other definitions for chess that I've seen before include "Pure-skill board game" , "Ancient war game whose name may have derived for the Persian for 'king'" , "Pieces moved in this" , "Game involving mates" , "show" .)
'the' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.
'mating game' is the wordplay.
'mating' becomes 'chess' (I can't justify this - if you can you should give a lot more credence to this answer).
'game' becomes 'match' (eg a football match).
'chess'+'match'='CHESS MATCH'
Can you help me to learn more?