The Germans have combined the two, literally round-by-round.
The rules are simple. There is one round of chess – and then one round of boxing. Punching power alternating with brainpower.
If you are wondering how they can move the pieces with their boxing gloves on, well, they take them off before the rounds of chess.
All in all, you have 11 rounds in which to either checkmate your opponent – or knock them out.