Keirin is a track race that starts our slow and ends up very fast.
There are many different kinds of track races performed on a track bike in a velodrome. They're all different and require different strategies and have different rules. The Keirin is one such race.
Keirin racing started in Japan in 1948. Today Keirin racing is still a very popular sport in Japan and good Keirin racers are paid very well. Keirin racing is a betting sport in Japan and the Japanese place bets on who will win each keirin race. In 2000 keirin racing finally became an Olympic sport.
A keirin race is done with 6-9 track cyclists who race in a line. Line up is often determined by drawing lots. The race starts with the keirin cyclists lining up behind the pacer on the track. A pacer can be a motorcycle, a tandem bike or something else that can keep the racing cyclists at a standard pace for several laps.
The pacer starts the race by going slow while the racers ride behind him in a straight line. The pacer will continue to go a little faster with each lap. Meanwhile, they keirin racers will try to get a better position during these paced laps by riding up on the bike in front of him and trying to squeeze his way in front.
When the pacer leaves the track the real racing begins. The last 2-3 laps of the race is when the racers will sprint for the finish line. The winner is determined by who ever goes over the finish line first. Keirin races often finish going about 75 km/h. The whole race is about 2 km, that's 5-8 laps depending on the size of the track.
