JINJU, South Korea: Gangta, his neck muscles rippling, butts his head against a pine tree. Like a prizefighter, he does roadwork on a hilltop training ground, dragging a 200-kilogram tire filled with rocks in stoic plods.

"Since he's an animal, I can't teach him skills. All I can do is build up his muscles and stamina," said Kang Myoung-chul, Gangta's owner. "Technique is something he's either born with or learns the hard way in the ring."

Gangta, or "Power Punch," is a 10-year-old fighting bull weighing 835 kilograms, or 1,840 pounds. He is also a three-time heavyweight national champion, a star in a sport that once meant as much to Koreans as the Kentucky Derby or Formula One does to some Americans.