Olympics-Clues to cauldron lighter lie in past, or future...

By Martin Quin Pollard

BEIJING (Reuters) - Those seeking clues to the traditional mystery of who will light the Olympic cauldron at the Games Opening Ceremony on Friday evening will be looking at precedent.

When China has hosted global sporting events over the past two decades - the 2008 Beijing 2008 Olympics, the 2010 Asian Games, the 2014 World Youth Olympics and the 2007 Asian Winter Games - the final torchbearer has been an Olympic medallist.

In 2008, three-times Olympic champion gymnast Li Ning lit the cauldron. While China has a far shorter list of Winter Games medallists to choose from, it still has plenty of options.

These include China's most decorated Winter Olympian, short track speed skater Wang Meng, and its first figure skating pairs gold medallists, Shen Xue and Zhao Hongbo.

On paper, a favourite is China's first Winter Olympic gold medallist, short track speed skater Yang Yang.

Yang is a household name in China, was closely involved in Beijing's winning bid in 2015 to host the Games and has been a torchbearer before, for the 2008 Beijing Games and the 2014 Summer Youth Olympics in Nanjing.

But Yang is not a lock-in.

"At first, I thought it would be Yang Yang, but Yang Yang recently appeared in public, so she is definitely not on the list to light the flame," Li Longmou, a Chinese Winter sports commentator told Reuters.

"Because lighting the flame is a top secret. Look at which athletes have not made a public appearance, it is possible they'll be the ones chosen."

Of those who have kept out of the spotlight, Li said triple Olympic gold medallist short track speed skater Zhou Yang could get the nod. But he has his eye on China's first Winter medallist, speed skater Ye Qiaobo, who won silver in 1992 in