At the Beijing Olympics, the Korean martial art was plagued by scoring problems and nearly thrown out of the games altogether.
Athletes complained their kicks weren't registered by the corner judges. And the results of one women's heavyweight bout were overturned after officials reviewed video footage and admitted the judges were wrong.
Since then, the sport's governing body has overhauled its scoring system. It introduced electronic body protectors that automatically record kicks and punches when they are delivered with enough force, though head kicks are still scored manually. The London Games will be the first Olympics to use the new system.
Any more controversy would be bad news for taekwondo. After the games, taekwondo will be reviewed alongside other sports by the International Olympic Committee to decide if it should stay in the games.
"Taekwondo scoring is much more objective now," said Jean-Marie Ayer, secretary-general of the World Taekwondo Federation. "It would be very bad luck if we had a lot of protests in London."
Most athletes and coaches agree electronic scoring makes taekwondo more objective since kicks and punches are tracked by a computer system, not the human eye.
"The electronic scoring system should eliminate protest and any feeling of injustice among athletes," said Jean Lopez, a U.S. Olympic team coach. "It's a step in the right direction and makes the sport much more fair."
Also new is the use of video replays. Coaches now have the right to at least one appeal if they think their fighter has scored a head kick that wasn't counted. But they will have to use their video replay card judiciously; they lose their right to appeal if they are wrong, though all medal matches will give coaches a new video replay card if they have previously lost it.
Another new rule penalizes athletes for inactivity — after 10 seconds, referees can give players warnings for not trying to fight. "That will make fights more interesting for spectators," Ayer said. The new rule means athletes won't be allowed to just back off if they are ahead and worried about losing their lead.
There should be little concern about that when the men's 58-kilogram contest starts on Wednesday.
Top-ranked Joel Gonzalez of Spain is among the sport's most dynamic fighters and will be looking for his first Olympic medal. But he could face serious competition from Lee Dae-hoon, South Korea's big hope. Lee normally fights in a heavier weight category, in which he won last year's world championship.
On the women's side, the action is likely to be fast-paced in the 49-kilogram division, where fighters often deliver numerous combination kicks with astonishing flexibility.
Beijing gold medallist Wu Jing Yu of China will be defending her title from fighters including Yang Shu Chun of Taipei, controversially disqualified from the 2010 Asian Games for wearing illegal sock sensors. Yang has been on a hot streak since then, taking silver at last year's world championships and winning this year's Asian championships.
Spain's Brigitte Yague will also be trying to win her first Olympic medal after previously winning the world championship in 2009. Yague said she isn't worried about the pressure of competing, but thrives on it. "I like the feeling the fights give me," she said. "It's a good feeling."