Every tournament organized by the Professional Darts Corporation (PDC) is held according to the rules established by the Darts Regulation Authority (DRA).
The DRA is responsible for developing the rules, maintaining discipline within the PDC and also for the anti-doping program in cooperation with UK Sport. Yet there are also some unwritten rules in the sport of darts, and Matthew Edgar discusses them in the most recent video on his YouTube channel Edgar TV.
Among other things, Edgar (himself a former PDC player) talks about the handshake given at the beginning and end of each match by the players to each other and also to the referee and writers. This handshake is not an obligation, but is still seen as a sign of respect.
You can watch the full video below!