In Beijing, China's National Judo Team are in the midst of winter training, under the guidance of coach Chung Hoon. The South Korean helped lead the PRC's men to major breakthroughs at this year's Rio Olympics. Chung now is hoping for more success, at the next Summer Games in Tokyo, in 2020. 

More than 100 athletes have been summoned to Beijing to train with China's national judo team. 90 percent of these competitors had never trained under Chung Hoon, who is pushing them, hard.

"For me, it's really unthinkable to training four times a day. I have not trained like this for maybe 10 years. I tried my best to carry on," said Yu Song, China judoka.

Chung implemented his rigorous training schedule before the Olympics in Rio. It took the squad three months to adjust, but positive results would follow, as Cheng Xunzhao's bronze medal in the 90-kilogram division marked the first podium finish by a Chinese male judoka at the Summer Games. Now the South Korean coach hopes his methods can help his team soar even higher at Tokyo 2020.

"Training is very hard. We hope to pick members for the next Olympics. These young athletes have a lot of room to improve, in both physical strength and improving their technique. The question is who can persevere. I believe some will make it to Tokyo," said Chung Hoon, China coach.

Chung's contract with China's national team ends in a month, but officials say they are eager to renew his deal, in an effort to achieve even more success on the mat.