In the World Grand Prix darts tournament, players must hit a double to begin scoring in a leg.
This format is called double-start. A player’s opening darts do not reduce the score until one of them lands in a double segment or the bullseye, which counts as the inner double. After the starting double is hit, ordinary scoring continues.
The World Grand Prix is unusual among major televised darts events because most x01 tournaments use a straight-start format. The event was first held in 1998 and is traditionally associated with the Citywest Hotel in Dublin, although venues and locations have changed. The requirement applies at the start of each leg, not merely at the beginning of a match, and it is distinct from the double required to finish a standard leg.