Hi,
area https://www.openstreetmap.org/way/159628079 does not look like a horse racetrack (https://wiki.openstreetmap.org/wiki/Tag:sport=horse_racing). I think it is the area of an equestrian center (https://keio-equestrian.com/) and should be tagged as one, see
https://wiki.openstreetmap.org/wiki/How_to_map_a#Riding_centre_(equestrian)
https://www.openstreetmap.org/way/674075993 (example)