HANDAN (China) • Buried waist-deep in ice for more than an hour and wearing nothing but a pair of swimming shorts, the man known in China as "Polar Bear" shivered but laughed at the challenge.
"At the moment, I feel very good," said Mr Cui Deyi, his torso exposed to near-freezing winter temperatures in the northern Chinese city of Handan on Saturday.
He is one of an elite group of global competitors testing humanity's ability to withstand extreme cold.
"I could continue at least another hour," said Mr Cui, with the steely confidence of a man who was reportedly submerged for 75 minutes in near-freezing waters off the coast of Norway in 2011.
With fragments of ice pressing against his lower body, the rotund athlete's arms were rocked by shivers. But that did not prevent him from winning several games of Chinese chess.
I'm using chess to test my ability to withstand cold and to see if my thoughts and hand reactions are affected.
MR CUI DEYI, who is one of an elite group of global competitors testing humanity's ability to withstand extreme cold
At rapid-fire speed, he slammed pieces down on a board in front of his transparent tub, securing victory against a local opponent.
"I'm using chess to test my ability to withstand cold and to see if my thoughts and hand reactions are affected," he added, still half-submerged.
Mr Cui hails from Huangshan in the eastern province of Anhui and began competing in cold endurance contests around a decade ago, after years of swimming in rivers and lakes during winter.
"Other people would shiver a lot after five minutes or so. But I could do half an hour or an hour with no problems," he said. "So, I slowly started to turn it into a profession".
Winter swimming, which sees enthusiasts breaking into iced-up waterways for dips is said to stave off illness and is popular in many parts of China. It even has government backing. There are several hundred Chinese clubs dedicated to it - including one in Handan, which organised Mr Cui's challenge beside a half-frozen lake named Yiquan.
Local winter swimming enthusiasts said their endurance paled before the man known as the "Polar Bear of Huangshan".