Two speed skaters run at a time around the 400 meter ice track counter-clockwise,
like the track and fields competition.
Whether the skater runs incourse or outcourse at the start is decided by lot.
Since the incourse is shorter than the outcourse, the two skaters must exchange their courses at the back straight,
the other side of the finish line,
so that the total distance they run is equal.
There are 500 meters, 1000 meters, 1500 meters, 3000 meters, 5000 meters, and 10000 meters races.
The winner and the positions are decided in a single race.
However 500 meters is the exception.
The skaters rush at maximum velocity into the second corner
where outside skater gets the advantge of the inside skater.
So the new rule is that, by exchanging the starting tracks, the skaters must run twice
and compete for the time sum of the two races.
Time measurement of the speed skating starts with the pistol and counts until the skater crosses the beam at the finish line.
When the starter triggers his pistol, the strobo light sends electric signal to the timer.
The finish is when the skate blade head crosses the beam.
So the beam is set very close to the ice surface.
Modern devices made it possible that the spectators know the lap time.
Also the laps left to go around is seen on the scoreboard.
On-line highspeed video made the finish judgement clear and visible
to the judges, spectators, newspaper, and TV watchers.
This is the integrated system similar to the one for Alpine skiing.
Short track speed skating has the individual races of 500 meters, 1000 meters, 1500 meters, 3000 meters, and the relay races of 3000 meters, 5000 meters, etc.
There are a lot of defferences between the short track race and the normal speed skating.
The short track is usually 111m long and 8 skaters start at once.
The winners take part in the next tournament until the final race.
The relay race uses a very unique way to take over the team mate.
Instead of handing over the baton, the skater pushes the next skater's hip with both hands.
Since many skaters are running at a time, judgement at the goal line sometimes becomes very difficult.
The slit video camera aiming at the goal line captures the rushing skaters at every 1/1000 second and shows them on the screen monitor.
Thus the skaters' time and the position are accurately decided.
The photo judgement of old days needed time for film development.
But the slit video camera made it possible to show the picture in an instant.
Also the color system can capture the distinct color of the skaters uniform.
