The sport started in Japan and dates to 1948, when it was created specifically as a betting sport. Even now it remains just one of four sports upon which betting is legal (the others being horse racing, boat racing, and Formula 1).
The sport is highly regulated in Japan, because of the gambling involved. Before each race, cyclists announce their tactics so people know how to bet. For example, a rider may say he will ride seiko, staying out front but not getting aggressive until the very end. Riders’ positions within the pace line often play to specific strengths, like sprinting or blocking. The sport requires exceptional endurance, as top-tier racers—who can earn many hundreds of thousands of dollars annually—may compete in as many as a dozen races a day during meets that last four days. Competitors are housed in dormitories and denied access to the Internet or phones, to prevent cheating or other shenanigans that may affect the betting.