(Reuters) - Focus on rugby sevens at the 2020 Tokyo Olympics:
THE ABSOLUTE BASICS
* A variation of the 15-aside rugby union game, sevens gets its name from the number of players on each team -- three forwards and four backs.
* With two seven-minute halves, sevens is much shorter than the 15-man game but the 12 teams in both the men's and women's tournaments play up to six matches over three days.
* With fewer players on the field, sevens offers more opportunity for scoring but the intensity makes lung-busting demands on players, who have to be able to sustain a high level of performance throughout the contest.
HOW MANY MEDALS?
There is one gold medal up for grabs in both the men's and women's tournaments.
WHAT HAPPENED IN RIO?
Fiji won the inaugural men's tournament in fine style by thrashing Britain 43-7 in the final, securing the Pacific island nation its first Olympic gold medal amid emotional scenes.
Australia were the first women's champions, 24-17 winners over New Zealand in the gold medal final at Deodoro Stadium.
WHAT CAN WE EXPECT IN TOKYO?
New Zealand, winners of more sevens honours than any nation by far, have plenty to prove after failing to win a title in Rio and it would be a major surprise if they did not bag one of the gold medals in Tokyo.
Fiji will again be hard to beat on the men's side if coach Gareth Baber can get a similar performance out of the talent-packed squad to that which Ben Ryan inspired in Rio, while South Africa's 'Blitzboks' should be involved in the medal rounds.
The women's teams from Canada and the United States are always strong and Britain will provide the best hope of medals for Europe.
In a reverse of the order from Rio, the men's tournament will be first in Tokyo with the women providing the finale on the middle Saturday of the Games.
WHEN IS IT HAPPENING?
WHERE IS IT HAPPENING?
HOW DID WE GET HERE?
The foundation myth has it that rugby union was born when William Webb Ellis picked up the ball and ran with it during a football match at Rugby School in England in 1823.
The game was played in its full version at four Olympic Games from 1900 until 1924. Sevens, invented in Scotland in the 1880s, made its Olympic debut in Rio.
WELL FANCY THAT
The United States were reigning men's Olympic rugby champions for 92 years after winning gold in Paris in 1924.
(Reporting by Nick Mulvenney, editing by Peter Rutherford)