What to know about Olympic rugby sevens in five key points:

+ Rugby sevens makes its debut in Rio. Previously there had been a 15-a-side rugby union competition between 1900 and 1924, thanks largely to Pierre de Coubertin, the man behind the launch of the modern Olympics who played and refereed the sport.

+ Rugby sevens will be able to boast one of the superstars of the oval ball game in New Zealand's code-swapping back Sonny Bill Williams. Bryan Habana missed out on selection for South Africa, with most teams opting for sevens specialists rather than drafting in 15s stars. Williams, however, is an exception, his offloading skills and physicality making him a perfect fit for the Gordon Tietjens-coached All Blacks and arguably the poster boy for World Rugby going into the Olympics. Williams' sister Niall made the women's team. "I'm proud of her, but at the same time there are a lot of media here and a lot of spotlight on myself and my sister, but for us it's not about us two," said Sonny Bill.

+ The International Olympic Committee (IOC) accepted rugby sevens for the Rio Games and also Tokyo in 2020 in a vote held in October 2009. In Rio, there are 12 teams in three pools of four drawn up by seeding. A round-robin format follows, with the two top teams from each pool plus the two best-placed third-placed teams advancing to the Cup quarter-finals, with lower-placed teams battling it out in the Plate and Bowl competitions at the 15,000-capacity Deodoro stadium.

+ The roots of rugby sevens can be traced back to the Scottish Borders, where a first tournament was organised in 1883. It was only 100 years later, however, that a first World Cup was organised. The World Sevens Series was inaugurated in 1999 and currently consists of 10 stages across the globe.

+ Played on a full-size pitch, sevens is not for the faint-hearted, the slightest defensive error likely to be fully exploited by players whose technical skills and speed are often much better than the average 15s international. Each match consists of two seven-minute halves with the exception of the final when each half is extended by three minutes. Should the final finish with the sides equal, the game goes to sudden-death extra-time, the first team to score winning.

+ Defending two-time world champions Fiji, chasing a first ever Olympic medal, are considered favourites, but the beauty of sevens is that upsets can happen, as seen by unheralded Spain beating Samoa for the final spot in the men's competition. New Zealand are fancied in the women's competition, with Canada, Britain and France expected to threaten in their August 6-8 showpiece, the men taking to the pitch between August 9-11.

Source: AFP