Celebrity, super-mum and one of the most feared judo champions of her time, Japan's Ryoko Tani has put family matters on hold to compete for a record third consecutive gold at the Beijing Olympics.

Japanese women's Judoka Ryoko Tani arrives at the Beijing airport yesterday to participate in the Beijing 2008 Olympic Games. [Agencies]

The first woman judoka to successfully defend an Olympic title, Tani will spearhead a team with lofty expectations, but one facing an uphill battle to match its extraordinary Athens haul of eight gold medals.

First up in the extra-lightweight (48kg) class when the judo competition begins on Saturday, the pint-sized 32-year-old will open Japan's campaign in a strong group featuring France's Frederique Jossinet, who she defeated in the final at Athens.

Tani, who by leaving the dojo in 2005 to raise her baby boy for two years ended an unbroken run of six world championships dating back to 1993, has made it clear that motherhood has not softened her.

Months after returning to the mat in 2007, Tani defeated Cuba's Yanet Bermoy to win a record seventh world championship in Brazil last September.

"In the last four years there have been a lot of experiences for me outside of judo, which have expanded my potential," Tani said in Tokyo last month.

In Beijing, the 1.46m-tall Tani will be suiting up as a wily veteran of four previous Olympics, a fighter who has tasted disappointment and glory in equal shares.

She entered the Olympic arena at the 1992 Barcelona Games as Ryoko Tamura, an unheralded 16-year-old. There, she stunned the world and a string of older, more-fancied opponents but lost to France's Cecile Nowak in the final bout.

An adoring Japanese public nicknamed the silver medalist "Yawara-chan", because of her resemblance to a young judoka heroine in a popular comic book.

Tani returned as a battle-hardened double world champion at Atlanta in 1996, but despite an 84-match winning streak and overwhelming favorite status, was upset by DPR Korea's Kye Sun-hui in the final.

Under enormous pressure in Sydney four years later, Tani needed only 36 seconds to win gold, throwing Russia's Lyubov Bruletova to win automatically with an ippon and finally mount the top of the podium.

"It's like meeting your first love again after eight years apart," a tearful Tani said.

Tani, who married Olympic baseball player Yoshitomo Tani in 2003, has advertised everything from rice to do-it-yourself goods on Japanese television, but her comic book looks and bubbly public persona belie a ruthless streak on the competition mat.

When she fought her childhood idol, Britain's Karen Briggs, at Barcelona in 1992, she dislocated her shoulder, and kept attacking the injury after her opponent wrenched the joint back into its socket. Briggs, in intense pain, was eventually disqualified for passivity.

"She pushes and pushes and then, at the end, she stings," French coach Stephane Traineau said after his charge Jossinet lost to Tani in the Athens final.

Underscoring the huge expectations from home fans in Japan, Tani will train at a secret dojo in Beijing away from teammates during evenings.

"It is because she is so key to the team's morale," said an official at the dojo.