LONDON - Yang Xiuli looks to become the most successful judoka in women's -78kg judo at the Olympic Games when she starts her title defence on Thursday here.

It will be bumpy for Yang on her way to be the first woman to win this event twice at the Olympics as Yoko Tanabe of Japan by far is the only athlete to have two medals - both silver - in this category.

Yang, 29, could meet Paris world champion Audrey Tcheumeo of France and world championship runner-up Akari Ogata of Japan, all drawn into the lower half of the pool.

Yang defeated Tcheumeo twice in their three meetings and got an upper hand in both her encounters with Ogata.

The other strong contenders for the second heaviest class in women's event include American Kayla Harrison and Brazilian Mayra Aguiar.

Harrison, 22, has the ambition to to become her country's first female Olympic champion in judo.?The 2010 world champion and 2011 bronze medalist beat Yang in this year's Dusseldorf Grand Prix in the final to bag the title.