Additionally , Europe hosts professional competitions known as pentathlons after the ancient Greek Olympic competitions , in which straight rail is featured as one of five billiards disciplines at which players compete , the other four being 47.1 balkline , cushion caroms , 71.2 balkline and three-cushion billiards .
The other four are called 47.1 balkline , cushion caroms , 71.2 balkline and three-cushion billiards .