This street skateboarder could deliver Japan’s first gold.

TOKYO — Past the baseball fields at Ojima Komatsugawa Park is a quiet edge where one of Japan’s leading Olympians got his start.

It is a place that sits quietly and unnoticed most days. Take a closer look: The stone steps leading toward the Kyunaka River are worn smooth by the grinding power of a thousand skateboards. The smooth, curved-steel hand rails beg to be ridden. A withered wooden quarter pipe is wedged under the bridge, next to a sleeping man. A sign warning that skateboarding is not allowed has been uprooted and tossed in the bushes.

Yuto Horigome grew up nearby, on the third floor of a 12-story apartment with his parents and two younger brothers. His father, Ryota Horigome, a Tokyo taxi driver, used to skateboard, too. When he married, he promised he would stop, because skateboarding in Japan was long seen as an activity for aimless renegades; it was time to get more serious with life.

But he took young Yuto to the park and handed him a skateboard. And on Sunday, Yuto Horigome, an unassuming 22-year-old from the east side of Tokyo, might become Japan’s first gold medalist — if he can beat the far more famous and rich Nyjah Huston of the United States in street skateboarding.

It is an event of imagination on rails, stairs and ramps. And the riverside edge of the park is where Horigome’s imagination flourished. On Friday, the same day that his father came to visit where it began, Yuto posted photographs to Instagram showing the two of them together at this very spot many years ago.

“It’s a once-in-a-lifetime chance,” Ryota said, 48 hours before the scheduled final of the Olympic contest. “But I have a heavy weight in my stomach.”

Kim Sang-woo contributed reporting.