If Japanese elementary and middle school students were asked what the coolest sports are, many are likely to mention skateboarding, where riders are able to perform a variety of tricks and display dynamic motion on a single board with four small wheels attached; in-line skating, where skates with a single row of wheels fixed to each boot allow skaters to display extreme moves not possible in other events; and bicycle motocross (BMX), where riders compete over severe natural terrain (or on the streets), employing high-level riding techniques. In traditional sports, the main objective usually is to compete for the best time or highest points. But in these sports, competition is based on performance and style. These and similar events are known as extreme sports, or X-sports for short. The three sports introduced above, known as B3 (bikes, boards, and blades), are especially popular, but other X-sports include climbing, bodyboarding, surfing, and bungee jumping, as well as winter sports like snowboarding, skiboarding, and jet skiing. In the United States, the X-Games--considered the world championship of X-sports--was first sponsored by a cable television network in 1995, and has since been held annually, moving to a new city every other year. X-sports first came into the spotlight in Japan during the summer 1999 X-Games, held in San Francisco, California, where three Japanese in-line skaters became champions in their respective events. Eito Yasutoko, 17, won the men's aggressive in-line vert--an event in which skaters perform various tricks on the half-pipe, so called because it resembles the inside of a pipe that has been cut in half. Eito, whose parents were both professional roller skaters, began roller-skating at age two before switching to in-line skating at age eight. Today he and his 14-year-old brother, Takeshi--who also took part in the 1999 games--are among the world's top skaters. Ayumi Kawasaki, 16, winner of the women's aggressive in-line vert, began in-line skating at age 9 and became the youngest champion ever at an event held in Venice Beach, California, when she was 12. And Sayaka Yabe won her second title in the women's aggressive in-line street event, where skaters perform tricks on a treacherous obstacle course. In the 2000 X-Games, held once again in San Francisco in August, Eito and Takeshi Yasutoko won the gold and silver medals, respectively, in the men's in-line vert. Although Kawasaki could not defend her title in the women's in-line vert, she still finished a very close second. Yabe unfortunately placed fourth in her event. Sports like skateboarding and mountain biking have already been popular for the last 10 years. X-sports as a whole, boasting a rich lineup of exciting events, will no doubt only grow more and more popular. Photo: An in-line skater jumps high into the air during a performance on the half-pipe. (Hajime Uchida)