Section of launch, essentially, in which master gets mates on board (5)
I believe the answer is:
chess
'board' is the definition.
(chess board is a kind of board)
'section of launch essentially in' is the wordplay.
'section of' indicates a hidden word.
'CHESS' can be found hidden inside 'launch essentially in'.
'which master gets mates on' acts as a link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for chess that I've seen before include "Game with kings and queens" , "that has over thirty men on board" , "Sixteen-men-a-side game" , "form of battle" , "show" .)