The 63-year-old was fishing in a mountain creek when the 190-centimetre (6-foot 3-inch) creature set upon him in what he said was an unprovoked attack.
In scenes seemingly reminiscent of Leonardo Di Caprio’s epic tussle with an angry bear in the Oscar-winning film “The Revenant” — Atsushi Aoki was bitten and scratched repeatedly, including on his head.
“The bear was so strong, and it knocked me down,” Aoki told Tokyo Broadcasting System. “It turned me over and bit me right here,” he added, pointing to his bandaged leg.
But instead of trying to outrun the beast — an Asian black bear — the fisherman decided he would use his well-honed karate skills.
After assuming a fighting stance with his right fist in front of him, Aoki jabbed at his attacker’s eyes, which sent the creature scrambling away into the woods.
“I thought it’s either ‘I kill him or he kills me,'” Aoki told public broadcaster NHK.
The plucky fisherman managed to get back to his car and get himself to a hospital in Gunma, northwest of Tokyo, despite the mauling that left him with injuries to his head, arm and leg.
“He drove himself to hospital, and he even remembered to grab the fish that he had caught,” a local police officer told AFP.
The ursine adventure was hailed in the Japanese press as a man-versus-nature tale of triumph.
“Man fights off bear with bare hands!” the Nikkan Sports tabloid screamed.
Despite media excitement over the episode, authorities in Japan advise against this course of action when confronted by one of Japan’s numerous wild bears.
Earlier this year four people were killed in separate bear attacks.