ASAHIKAWA, Hokkaido — Skirting a fresh pile of manure, I settle in behind the well-muscled, veiny flanks of a Banei racehorse.

The jockey helps me astride the dusty sled and tells me to brace myself. With the squeak of a horn, the gates fly open and the horse lurches forward. My body is snapped like a whip. Clouds of sand billow as we pass the horse in the next lane. The jockey encourages the animal, smacking its flanks with a leather switch, prodding it over and down two small hills.

This is Banei horse racing.