Keirin

The Olympic cycling sport of keirin was invented in Japan more than 70 years ago to raise money to rebuild the country after World War II. Now, fans bet billions of dollars a year on races, with the top riders earning huge sums. In each race, a pacemaker leads nine riders around a huge concrete velodrome, then leaves the track with around a lap and a half to go - the cue for a frantic finish as the competitors reach speeds of up to 70 kph. Along the way they block and shove each other, clash heads and often crash (the two Japanese characters used to write keirin mean "battle" and "wheel"). To prevent race fixing, the cyclists live in dorms, with no access to online technology. Their lives are ruled by ritual and fierce competition, from their rookie days at the Japan Keirin School near Mount Fuji to the annual Grand Prix final, whose winner takes home prize money of one million dollars. A small number of foreign riders are invited to compete in Japan every year and some, like Shane Perkins, have overcome culture shock to prosper in the home of keirin. The Olympic version - which has made stars of Chris Hoy, Jason Kenny and Victoria Pendleton - is being taken more seriously in Japan as Tokyo prepares to host the 2020 Olympics and Paralympics. In Keirin: War on Wheels, Justin McCurry, the Guardian's Japan and Korea correspondent, explores blue-collar Japan from a fascinating new perspective. His encounters with punters, pundits, veterans and rookies reveal parts of Japanese society and psyche rarely examined, learning lessons about country and culture that go far beyond the sporting realm.