Ten-pin bowling Bowling Championships. Ten-pin bowling has an international ranking system, as with many professional individual sports. This ten-pin equivalent is known as the World Ranking Masters and is made of three vast tours: the European, Americas and Asian bowling tours. Other minor tournaments, although major in their respective countries, include Britain's prestigious BTBA Nationals (BTBA National Championships), the Brunswick Ballmaster Open, Brunswick Euro Challenge in Greece, ETBF European Youth Championships, the European Gold Cup and the Mediterranean Challenge Cup. The world's premier amateur event is the WB/WTBA World Championships (World Bowling) which has been running since 1954 and is now held
Bowling ball diameter in the range of to . The surface of the ball is required to include markings to indicate the manufacturer's brand name, the name of the ball, the center of gravity (before drilling), the orientation of the core (the Pin), and the axes of the high and/or low radius of gyration (as applicable). Additionally, markings must include an individual serial number and the logo of the USBC. Holes are allowed to be drilled into a bowling ball for a variety of reasons, and bowlers must be able to demonstrate that such holes can be used as claimed. Up to