The name Sera Greeen Park Korakuen sounds more like a green park in a city for urban people spending their Sunday afternoon picknicking, but it is actually the opposite; a complex for outdoor and motorsports deep in the mountains. While the facility is most famous for its Motorcross circuit, there is also a carting circuit and big asphalted area.
The 740 meter long carting circuit is mainly used for carts and minibikes while the large asphalted area of over 5000 m2 is for gymkhana (and sometimes drifting). To use the carting circuit and gymkhana area, either them cost 4400 Yen for non-members and 3300 Yen for members. A year-long membership costs 7700 Yen for the first year and 4400 for the year after. Besides the discount for regular runs, each run will gather you 1 point and with 1 points you can get a free run.
The location is around 20 minutes by car west of Sera city, the biggest city in the vicinity of the facility. In case you do not have a car available, it would take around 1 hour by bus from the city center.
A link to the website can be found below:
And a link to the location on Google Maps: