The hot sun beat down on the hat-wearing packed crowd at the Le Bourget Sport Climbing Venue north of Paris as the Olympic sport climbing events opened with its new two-discipline format. Twenty of the best sport climbers in the world took a shot at four challenging problems in the men’s bouldering semifinal to earn half of the points needed to advance to the bouldering and lead combined final. 

Japanese climbers Sorato Anraku and Tomoa Narasaki led the way in qualifying with 69 and 54.4 points, respectively. Great Britain's Toby Roberts finished third with 54.1 points. 

Americans Colin Duffy and Jesse Grupper finished 11th and 18th, respectively. The two will have a chance to better their ranking and qualify for the combined final during the lead semifinal on Aug. 7. 

Nearly half of the climbers were unable to top any of the four boulders in Monday's qualifying event. No climber had completed a single boulder problem until Austria's Jakob Schubert — the 18th climber to start — topped the first boulder. He launched into the top half of the rankings and got the ball rolling for other competitors to top subsequent problems.

Japan’s two climbers, Anraku and Narasaki, dominated. Seventeen-year-old Anraku, the youngest climber in the field, wowed the crowd as he took on the first boulder with ease and topped it with two minutes left to spare. He breezed through the second boulder with even more proficiency, completing it in one minute. Out of the 25 possible points for each boulder, Anraku earned 24.9 and 25 points, respectively, setting him up for a strong performance. He heads into the lead semifinal as the top boulder competitor with 69 points awarded out of the possible 100 and a 14.6-point advantage over his compatriot in second.

"I'm happy that I topped two boulders, but I was frustrated that I couldn't do Boulder 4," Anraku said. His goal to reach the bouldering and lead combined final is only the beginning.

"Then I want to become the king of climbing," Anraku added.

The boulders constructed for the Olympics were so challenging that Anraku was the only climber to complete two. Only the top six climbers in the rankings were able to complete at least one problem. 

“We never know before,” Sam Avezou of France said of seeing the tough boulders for the first time when he stepped out to compete. “Sometimes the route setters overcook it a bit, sometimes [they] undercook it… These same route setters sometimes do it a bit easier, sometimes a bit harder, so we never know what we are going to face.”

Narasaki, in second, was one of only four climbers to top the final boulder, which involved a tricky foot transition to step over a small foothold and reach the last hold.

Great Britain’s Roberts trailed Narasaki by the narrow margin of 0.3 points. The top European competitor got close to topping the unbeatable third boulder but eventually fell off. He later topped the final boulder to finish in third.

"The boulders were really sort of crazy," Roberts said. "A very hard round — normally it wouldn't be that hard. I'm not sure of the exact result, but I can't imagine there have been too many tops. So yeah, a tough round but I'm here for it."

Host country favorite Avezou also had an impressive performance. The Frenchman finished fourth after solid attempts at the first two boulders and a strong top of the final boulder. 

The top eight climbers with the highest combined scores from the boulder and lead competitions will advance to the final.

Men's boulder semifinal (Top 8):

Sorato Anraku (JPN): 69 points
Tomoa Narasaki (JPN): 54.4 points
Toby Roberts (GBR): 54.1 points
Sam Avezou (FRA): 49.2 points
Adam Ondra (CZE): 48.7 points
Jakob Schubert (AUT): 44.7 points
Hannes Van Duysen (BEL): 34.3 points
Hamish McArthur (GBR): 34.2 points

RESULTS